diff --git a/.coveragerc b/.coveragerc
index 96190b454..02d211c56 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -11,8 +11,3 @@ exclude_lines =
     pragma: NO COVER
     # Ignore debug-only repr
     def __repr__
-    # Ignore pkg_resources exceptions.
-    # This is added at the module level as a safeguard for if someone
-    # generates the code and tries to run it without pip installing. This
-    # makes it virtually impossible to test properly.
-    except pkg_resources.DistributionNotFound
diff --git a/google/cloud/pubsub_v1/publisher/client.py b/google/cloud/pubsub_v1/publisher/client.py
index e3266e57f..3e668533d 100644
--- a/google/cloud/pubsub_v1/publisher/client.py
+++ b/google/cloud/pubsub_v1/publisher/client.py
@@ -17,7 +17,6 @@
 import copy
 import logging
 import os
-import pkg_resources
 import threading
 import time
 import typing
@@ -35,15 +34,11 @@
 from google.cloud.pubsub_v1.publisher._sequencer import ordered_sequencer
 from google.cloud.pubsub_v1.publisher._sequencer import unordered_sequencer
 from google.cloud.pubsub_v1.publisher.flow_controller import FlowController
+from google.pubsub_v1 import gapic_version as package_version
 from google.pubsub_v1 import types as gapic_types
 from google.pubsub_v1.services.publisher import client as publisher_client
 
-try:
-    __version__ = pkg_resources.get_distribution("google-cloud-pubsub").version
-except pkg_resources.DistributionNotFound:
-    # Distribution might not be available if we are not running from within a
-    # PIP package.
-    __version__ = "0.0"
+__version__ = package_version.__version__
 
 if typing.TYPE_CHECKING:  # pragma: NO COVER
     from google.cloud import pubsub_v1
diff --git a/google/cloud/pubsub_v1/subscriber/client.py b/google/cloud/pubsub_v1/subscriber/client.py
index 9c12a0bfb..0d0d36a0c 100644
--- a/google/cloud/pubsub_v1/subscriber/client.py
+++ b/google/cloud/pubsub_v1/subscriber/client.py
@@ -15,7 +15,6 @@
 from __future__ import absolute_import
 
 import os
-import pkg_resources
 import typing
 from typing import cast, Any, Callable, Optional, Sequence, Union
 import warnings
@@ -27,6 +26,7 @@
 from google.cloud.pubsub_v1.subscriber import futures
 from google.cloud.pubsub_v1.subscriber._protocol import streaming_pull_manager
 from google.pubsub_v1.services.subscriber import client as subscriber_client
+from google.pubsub_v1 import gapic_version as package_version
 
 if typing.TYPE_CHECKING:  # pragma: NO COVER
     from google.cloud.pubsub_v1 import subscriber
@@ -34,13 +34,7 @@
         SubscriberGrpcTransport,
     )
 
-
-try:
-    __version__ = pkg_resources.get_distribution("google-cloud-pubsub").version
-except pkg_resources.DistributionNotFound:
-    # Distribution might not be available if we are not running from within
-    # a PIP package.
-    __version__ = "0.0"
+__version__ = package_version.__version__
 
 
 class Client(subscriber_client.SubscriberClient):
diff --git a/google/pubsub_v1/gapic_version.py b/google/pubsub_v1/gapic_version.py
new file mode 100644
index 000000000..51b84e9a6
--- /dev/null
+++ b/google/pubsub_v1/gapic_version.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+__version__ = "2.13.11"  # {x-release-please-version}
diff --git a/google/pubsub_v1/services/publisher/async_client.py b/google/pubsub_v1/services/publisher/async_client.py
index d12eeb1da..6a282d7dd 100644
--- a/google/pubsub_v1/services/publisher/async_client.py
+++ b/google/pubsub_v1/services/publisher/async_client.py
@@ -27,7 +27,8 @@
     Type,
     Union,
 )
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core.client_options import ClientOptions
 from google.api_core import exceptions as core_exceptions
@@ -1558,14 +1559,9 @@ async def __aexit__(self, exc_type, exc, tb):
         await self.transport.close()
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("PublisherAsyncClient",)
diff --git a/google/pubsub_v1/services/publisher/client.py b/google/pubsub_v1/services/publisher/client.py
index 32b1def3d..436c25a2d 100644
--- a/google/pubsub_v1/services/publisher/client.py
+++ b/google/pubsub_v1/services/publisher/client.py
@@ -29,7 +29,8 @@
     Union,
     cast,
 )
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core import client_options as client_options_lib
 from google.api_core import exceptions as core_exceptions
@@ -1753,14 +1754,9 @@ def test_iam_permissions(
         return response
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("PublisherClient",)
diff --git a/google/pubsub_v1/services/publisher/transports/base.py b/google/pubsub_v1/services/publisher/transports/base.py
index d441f8113..79ec2d4ff 100644
--- a/google/pubsub_v1/services/publisher/transports/base.py
+++ b/google/pubsub_v1/services/publisher/transports/base.py
@@ -15,7 +15,8 @@
 #
 import abc
 from typing import Awaitable, Callable, Dict, Optional, Sequence, Union
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 import google.auth  # type: ignore
 import google.api_core
@@ -30,14 +31,9 @@
 from google.protobuf import empty_pb2  # type: ignore
 from google.pubsub_v1.types import pubsub
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 class PublisherTransport(abc.ABC):
diff --git a/google/pubsub_v1/services/schema_service/async_client.py b/google/pubsub_v1/services/schema_service/async_client.py
index 1996a1e4f..262190ea3 100644
--- a/google/pubsub_v1/services/schema_service/async_client.py
+++ b/google/pubsub_v1/services/schema_service/async_client.py
@@ -27,7 +27,8 @@
     Type,
     Union,
 )
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core.client_options import ClientOptions
 from google.api_core import exceptions as core_exceptions
@@ -223,7 +224,7 @@ async def create_schema(
         schema: Optional[gp_schema.Schema] = None,
         schema_id: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gp_schema.Schema:
         r"""Creates a schema.
@@ -351,7 +352,7 @@ async def get_schema(
         *,
         name: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> schema.Schema:
         r"""Gets a schema.
@@ -450,7 +451,7 @@ async def list_schemas(
         *,
         parent: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSchemasAsyncPager:
         r"""Lists schemas in a project.
@@ -564,7 +565,7 @@ async def delete_schema(
         *,
         name: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Deletes a schema.
@@ -655,7 +656,7 @@ async def validate_schema(
         parent: Optional[str] = None,
         schema: Optional[gp_schema.Schema] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gp_schema.ValidateSchemaResponse:
         r"""Validates a schema.
@@ -769,7 +770,7 @@ async def validate_message(
         request: Optional[Union[schema.ValidateMessageRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> schema.ValidateMessageResponse:
         r"""Validates a message against a schema.
@@ -850,7 +851,7 @@ async def set_iam_policy(
         request: Optional[iam_policy_pb2.SetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Sets the IAM access control policy on the specified function.
@@ -969,7 +970,7 @@ async def get_iam_policy(
         request: Optional[iam_policy_pb2.GetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Gets the IAM access control policy for a function.
@@ -1090,7 +1091,7 @@ async def test_iam_permissions(
         request: Optional[iam_policy_pb2.TestIamPermissionsRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
         r"""Tests the specified permissions against the IAM access control
@@ -1151,14 +1152,9 @@ async def __aexit__(self, exc_type, exc, tb):
         await self.transport.close()
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("SchemaServiceAsyncClient",)
diff --git a/google/pubsub_v1/services/schema_service/client.py b/google/pubsub_v1/services/schema_service/client.py
index 45f013e91..b02ee14e6 100644
--- a/google/pubsub_v1/services/schema_service/client.py
+++ b/google/pubsub_v1/services/schema_service/client.py
@@ -29,7 +29,8 @@
     Union,
     cast,
 )
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core import client_options as client_options_lib
 from google.api_core import exceptions as core_exceptions
@@ -455,7 +456,7 @@ def create_schema(
         schema: Optional[gp_schema.Schema] = None,
         schema_id: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gp_schema.Schema:
         r"""Creates a schema.
@@ -583,7 +584,7 @@ def get_schema(
         *,
         name: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> schema.Schema:
         r"""Gets a schema.
@@ -682,7 +683,7 @@ def list_schemas(
         *,
         parent: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSchemasPager:
         r"""Lists schemas in a project.
@@ -796,7 +797,7 @@ def delete_schema(
         *,
         name: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Deletes a schema.
@@ -887,7 +888,7 @@ def validate_schema(
         parent: Optional[str] = None,
         schema: Optional[gp_schema.Schema] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gp_schema.ValidateSchemaResponse:
         r"""Validates a schema.
@@ -1001,7 +1002,7 @@ def validate_message(
         request: Optional[Union[schema.ValidateMessageRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> schema.ValidateMessageResponse:
         r"""Validates a message against a schema.
@@ -1096,7 +1097,7 @@ def set_iam_policy(
         request: Optional[iam_policy_pb2.SetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Sets the IAM access control policy on the specified function.
@@ -1216,7 +1217,7 @@ def get_iam_policy(
         request: Optional[iam_policy_pb2.GetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Gets the IAM access control policy for a function.
@@ -1337,7 +1338,7 @@ def test_iam_permissions(
         request: Optional[iam_policy_pb2.TestIamPermissionsRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
         r"""Tests the specified IAM permissions against the IAM access control
@@ -1392,14 +1393,9 @@ def test_iam_permissions(
         return response
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("SchemaServiceClient",)
diff --git a/google/pubsub_v1/services/schema_service/transports/base.py b/google/pubsub_v1/services/schema_service/transports/base.py
index 8035f7fd2..036562796 100644
--- a/google/pubsub_v1/services/schema_service/transports/base.py
+++ b/google/pubsub_v1/services/schema_service/transports/base.py
@@ -15,7 +15,8 @@
 #
 import abc
 from typing import Awaitable, Callable, Dict, Optional, Sequence, Union
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 import google.auth  # type: ignore
 import google.api_core
@@ -31,14 +32,9 @@
 from google.pubsub_v1.types import schema
 from google.pubsub_v1.types import schema as gp_schema
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 class SchemaServiceTransport(abc.ABC):
diff --git a/google/pubsub_v1/services/subscriber/async_client.py b/google/pubsub_v1/services/subscriber/async_client.py
index fb860596d..f0c38b043 100644
--- a/google/pubsub_v1/services/subscriber/async_client.py
+++ b/google/pubsub_v1/services/subscriber/async_client.py
@@ -30,8 +30,9 @@
     Type,
     Union,
 )
+
 import warnings
-import pkg_resources
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core.client_options import ClientOptions
 from google.api_core import exceptions as core_exceptions
@@ -231,7 +232,7 @@ async def create_subscription(
         push_config: Optional[pubsub.PushConfig] = None,
         ack_deadline_seconds: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Creates a subscription to a given topic. See the [resource name
@@ -416,7 +417,7 @@ async def get_subscription(
         *,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Gets the configuration details of a subscription.
@@ -528,7 +529,7 @@ async def update_subscription(
         request: Optional[Union[pubsub.UpdateSubscriptionRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Updates an existing subscription. Note that certain
@@ -624,7 +625,7 @@ async def list_subscriptions(
         *,
         project: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSubscriptionsAsyncPager:
         r"""Lists matching subscriptions.
@@ -749,7 +750,7 @@ async def delete_subscription(
         *,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Deletes an existing subscription. All messages retained in the
@@ -857,7 +858,7 @@ async def modify_ack_deadline(
         ack_ids: Optional[MutableSequence[str]] = None,
         ack_deadline_seconds: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Modifies the ack deadline for a specific message. This method is
@@ -991,7 +992,7 @@ async def acknowledge(
         subscription: Optional[str] = None,
         ack_ids: Optional[MutableSequence[str]] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Acknowledges the messages associated with the ``ack_ids`` in the
@@ -1112,7 +1113,7 @@ async def pull(
         return_immediately: Optional[bool] = None,
         max_messages: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.PullResponse:
         r"""Pulls messages from the server. The server may return
@@ -1261,7 +1262,7 @@ def streaming_pull(
         requests: Optional[AsyncIterator[pubsub.StreamingPullRequest]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> Awaitable[AsyncIterable[pubsub.StreamingPullResponse]]:
         r"""Establishes a stream with the server, which sends messages down
@@ -1370,7 +1371,7 @@ async def modify_push_config(
         subscription: Optional[str] = None,
         push_config: Optional[pubsub.PushConfig] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Modifies the ``PushConfig`` for a specified subscription.
@@ -1491,7 +1492,7 @@ async def get_snapshot(
         *,
         snapshot: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Gets the configuration details of a snapshot.
@@ -1613,7 +1614,7 @@ async def list_snapshots(
         *,
         project: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSnapshotsAsyncPager:
         r"""Lists the existing snapshots. Snapshots are used in
@@ -1743,7 +1744,7 @@ async def create_snapshot(
         name: Optional[str] = None,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Creates a snapshot from the requested subscription. Snapshots
@@ -1898,7 +1899,7 @@ async def update_snapshot(
         request: Optional[Union[pubsub.UpdateSnapshotRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Updates an existing snapshot. Snapshots are used in
@@ -2000,7 +2001,7 @@ async def delete_snapshot(
         *,
         snapshot: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Removes an existing snapshot. Snapshots are used in [Seek]
@@ -2107,7 +2108,7 @@ async def seek(
         request: Optional[Union[pubsub.SeekRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.SeekResponse:
         r"""Seeks an existing subscription to a point in time or to a given
@@ -2205,7 +2206,7 @@ async def set_iam_policy(
         request: Optional[iam_policy_pb2.SetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Sets the IAM access control policy on the specified function.
@@ -2324,7 +2325,7 @@ async def get_iam_policy(
         request: Optional[iam_policy_pb2.GetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Gets the IAM access control policy for a function.
@@ -2445,7 +2446,7 @@ async def test_iam_permissions(
         request: Optional[iam_policy_pb2.TestIamPermissionsRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
         r"""Tests the specified permissions against the IAM access control
@@ -2506,14 +2507,9 @@ async def __aexit__(self, exc_type, exc, tb):
         await self.transport.close()
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("SubscriberAsyncClient",)
diff --git a/google/pubsub_v1/services/subscriber/client.py b/google/pubsub_v1/services/subscriber/client.py
index 35d96b5b5..888af9883 100644
--- a/google/pubsub_v1/services/subscriber/client.py
+++ b/google/pubsub_v1/services/subscriber/client.py
@@ -31,8 +31,9 @@
     Union,
     cast,
 )
+
 import warnings
-import pkg_resources
+from google.pubsub_v1 import gapic_version as package_version
 
 from google.api_core import client_options as client_options_lib
 from google.api_core import exceptions as core_exceptions
@@ -510,7 +511,7 @@ def create_subscription(
         push_config: Optional[pubsub.PushConfig] = None,
         ack_deadline_seconds: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Creates a subscription to a given topic. See the [resource name
@@ -684,7 +685,7 @@ def get_subscription(
         *,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Gets the configuration details of a subscription.
@@ -785,7 +786,7 @@ def update_subscription(
         request: Optional[Union[pubsub.UpdateSubscriptionRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Subscription:
         r"""Updates an existing subscription. Note that certain
@@ -873,7 +874,7 @@ def list_subscriptions(
         *,
         project: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSubscriptionsPager:
         r"""Lists matching subscriptions.
@@ -987,7 +988,7 @@ def delete_subscription(
         *,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Deletes an existing subscription. All messages retained in the
@@ -1086,7 +1087,7 @@ def modify_ack_deadline(
         ack_ids: Optional[MutableSequence[str]] = None,
         ack_deadline_seconds: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Modifies the ack deadline for a specific message. This method is
@@ -1211,7 +1212,7 @@ def acknowledge(
         subscription: Optional[str] = None,
         ack_ids: Optional[MutableSequence[str]] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Acknowledges the messages associated with the ``ack_ids`` in the
@@ -1323,7 +1324,7 @@ def pull(
         return_immediately: Optional[bool] = None,
         max_messages: Optional[int] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.PullResponse:
         r"""Pulls messages from the server. The server may return
@@ -1461,7 +1462,7 @@ def streaming_pull(
         requests: Optional[Iterator[pubsub.StreamingPullRequest]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> Iterable[pubsub.StreamingPullResponse]:
         r"""Establishes a stream with the server, which sends messages down
@@ -1558,7 +1559,7 @@ def modify_push_config(
         subscription: Optional[str] = None,
         push_config: Optional[pubsub.PushConfig] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Modifies the ``PushConfig`` for a specified subscription.
@@ -1670,7 +1671,7 @@ def get_snapshot(
         *,
         snapshot: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Gets the configuration details of a snapshot.
@@ -1781,7 +1782,7 @@ def list_snapshots(
         *,
         project: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListSnapshotsPager:
         r"""Lists the existing snapshots. Snapshots are used in
@@ -1900,7 +1901,7 @@ def create_snapshot(
         name: Optional[str] = None,
         subscription: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Creates a snapshot from the requested subscription. Snapshots
@@ -2046,7 +2047,7 @@ def update_snapshot(
         request: Optional[Union[pubsub.UpdateSnapshotRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.Snapshot:
         r"""Updates an existing snapshot. Snapshots are used in
@@ -2140,7 +2141,7 @@ def delete_snapshot(
         *,
         snapshot: Optional[str] = None,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Removes an existing snapshot. Snapshots are used in [Seek]
@@ -2238,7 +2239,7 @@ def seek(
         request: Optional[Union[pubsub.SeekRequest, dict]] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pubsub.SeekResponse:
         r"""Seeks an existing subscription to a point in time or to a given
@@ -2339,7 +2340,7 @@ def set_iam_policy(
         request: Optional[iam_policy_pb2.SetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Sets the IAM access control policy on the specified function.
@@ -2459,7 +2460,7 @@ def get_iam_policy(
         request: Optional[iam_policy_pb2.GetIamPolicyRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
         r"""Gets the IAM access control policy for a function.
@@ -2580,7 +2581,7 @@ def test_iam_permissions(
         request: Optional[iam_policy_pb2.TestIamPermissionsRequest] = None,
         *,
         retry: OptionalRetry = gapic_v1.method.DEFAULT,
-        timeout: Optional[float] = None,
+        timeout: Union[float, object] = gapic_v1.method.DEFAULT,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
         r"""Tests the specified IAM permissions against the IAM access control
@@ -2635,14 +2636,9 @@ def test_iam_permissions(
         return response
 
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 __all__ = ("SubscriberClient",)
diff --git a/google/pubsub_v1/services/subscriber/transports/base.py b/google/pubsub_v1/services/subscriber/transports/base.py
index c1d2d8aff..2cf93a726 100644
--- a/google/pubsub_v1/services/subscriber/transports/base.py
+++ b/google/pubsub_v1/services/subscriber/transports/base.py
@@ -15,7 +15,8 @@
 #
 import abc
 from typing import Awaitable, Callable, Dict, Optional, Sequence, Union
-import pkg_resources
+
+from google.pubsub_v1 import gapic_version as package_version
 
 import google.auth  # type: ignore
 import google.api_core
@@ -30,14 +31,9 @@
 from google.protobuf import empty_pb2  # type: ignore
 from google.pubsub_v1.types import pubsub
 
-try:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
-        client_library_version=pkg_resources.get_distribution(
-            "google-cloud-pubsub",
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
+DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
+    client_library_version=package_version.__version__
+)
 
 
 class SubscriberTransport(abc.ABC):
diff --git a/owlbot.py b/owlbot.py
index 81ec371a2..0af937c4d 100644
--- a/owlbot.py
+++ b/owlbot.py
@@ -139,7 +139,7 @@
     # Emit deprecation warning if return_immediately flag is set with synchronous pull.
     s.replace(
         library / f"google/pubsub_{library.name}/services/subscriber/*client.py",
-        r"import pkg_resources",
+        r"from google.pubsub_v1 import gapic_version as package_version",
         "import warnings\n\g<0>",
     )
 
@@ -210,7 +210,7 @@
         raise Exception("Catch warnings replacement failed.")
 
     # Make sure that client library version is present in user agent header.
-    s.replace(
+    count = s.replace(
         [
             library
             / f"google/pubsub_{library.name}/services/publisher/async_client.py",
@@ -228,10 +228,13 @@
             library
             / f"google/pubsub_{library.name}/services/subscriber/transports/base.py",
         ],
-        r"""gapic_version=(pkg_resources\.get_distribution\(\s+)['"]google-cloud-pubsub['"]""",
-        "client_library_version=\g<1>'google-cloud-pubsub'",
+        r"""gapic_version=package_version.__version__""",
+        "client_library_version=package_version.__version__",
     )
 
+    if count < 1:
+        raise Exception("client_library_version replacement failed.")
+
     # Allow timeout to be an instance of google.api_core.timeout.*
     count = s.replace(
         library / f"google/pubsub_{library.name}/types/__init__.py",
@@ -282,7 +285,7 @@
 
     count = s.replace(
         library / f"google/pubsub_{library.name}/services/publisher/*client.py",
-        r"(\s+)timeout: Optional\[float\] = None.*\n",
+        r"(\s+)timeout: Union\[float, object\] = gapic_v1.method.DEFAULT.*\n",
         f"\g<1>timeout: TimeoutType = gapic_{library.name}.method.DEFAULT,",
     )
 
diff --git a/release-please-config.json b/release-please-config.json
index 939d477d1..909352415 100644
--- a/release-please-config.json
+++ b/release-please-config.json
@@ -5,6 +5,7 @@
         "release-type": "python",
         "extra-files": [
           "google/pubsub/gapic_version.py",
+          "google/pubsub_v1/gapic_version.py",
           {
             "type": "json",
             "path": "samples/generated_samples/snippet_metadata_google.pubsub.v1.json",
diff --git a/setup.py b/setup.py
index 1fa80c2ca..b38f1e04f 100644
--- a/setup.py
+++ b/setup.py
@@ -37,7 +37,7 @@
 
 dependencies = [
     "grpcio >= 1.38.1, < 2.0dev",  # https://github.com/googleapis/python-pubsub/issues/414
-    "google-api-core[grpc] >= 1.33.2, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.*,!=2.4.*,!=2.5.*,!=2.6.*,!=2.7.*",
+    "google-api-core[grpc] >= 1.34.0, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.*,!=2.4.*,!=2.5.*,!=2.6.*,!=2.7.*,!=2.8.*,!=2.9.*,!=2.10.*",
     "proto-plus >= 1.22.0, <2.0.0dev",
     "protobuf>=3.19.5,<5.0.0dev,!=3.20.0,!=3.20.1,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
     "grpc-google-iam-v1 >= 0.12.4, < 1.0.0dev",
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index b6b0ed782..54e27914f 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -4,7 +4,7 @@
 # Pin the version to the lower bound.
 # e.g., if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have google-cloud-foo==1.14.0
-google-api-core==1.33.2
+google-api-core==1.34.0
 proto-plus==1.22.0
 protobuf==3.19.5
 grpc-google-iam-v1==0.12.4