From e75dec15b8fc9a40886ed9daa98d8269db111382 Mon Sep 17 00:00:00 2001
From: Allen Zhang <allenzhang@live.com>
Date: Tue, 23 Mar 2021 14:46:02 -0700
Subject: [PATCH] Remove System.Linq.Async dependency. (#19745)

---
 eng/Packages.Data.props                       |  1 -
 .../src/Azure.ResourceManager.Core.csproj     |  1 -
 .../src/Extensions/AsyncPageableExtensions.cs | 37 +++++++++++++++++++
 .../src/ResourceOperationsBase.cs             |  1 +
 4 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 sdk/resourcemanager/Azure.ResourceManager.Core/src/Extensions/AsyncPageableExtensions.cs

diff --git a/eng/Packages.Data.props b/eng/Packages.Data.props
index bf10e24ba3fe2..31edab31cc0ca 100644
--- a/eng/Packages.Data.props
+++ b/eng/Packages.Data.props
@@ -72,7 +72,6 @@
     <PackageReference Update="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
     <PackageReference Update="Microsoft.CSharp" Version="4.5.0" />
     <PackageReference Update="System.Collections.Immutable" Version="1.3.1" />
-    <PackageReference Update="System.Linq.Async" Version="4.0.0" />
 
     <!-- Azure SDK packages -->
     <PackageReference Update="Azure.Core" Version="1.10.0" />
diff --git a/sdk/resourcemanager/Azure.ResourceManager.Core/src/Azure.ResourceManager.Core.csproj b/sdk/resourcemanager/Azure.ResourceManager.Core/src/Azure.ResourceManager.Core.csproj
index 0850e68ca8b06..d6ee2a51ea770 100644
--- a/sdk/resourcemanager/Azure.ResourceManager.Core/src/Azure.ResourceManager.Core.csproj
+++ b/sdk/resourcemanager/Azure.ResourceManager.Core/src/Azure.ResourceManager.Core.csproj
@@ -15,7 +15,6 @@
   <ItemGroup>
     <PackageReference Include="System.Collections.Immutable" />
     <PackageReference Include="Azure.ResourceManager.Resources" />
-    <PackageReference Include="System.Linq.Async" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/sdk/resourcemanager/Azure.ResourceManager.Core/src/Extensions/AsyncPageableExtensions.cs b/sdk/resourcemanager/Azure.ResourceManager.Core/src/Extensions/AsyncPageableExtensions.cs
new file mode 100644
index 0000000000000..4f6ddb3e28aea
--- /dev/null
+++ b/sdk/resourcemanager/Azure.ResourceManager.Core/src/Extensions/AsyncPageableExtensions.cs
@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Azure.ResourceManager.Core.Extensions
+{
+    internal static class AsyncPageableExtensions
+    {
+        public static async Task<TSource> FirstOrDefaultAsync<TSource>(
+            this AsyncPageable<TSource> source,
+            Func<TSource, bool> predicate,
+            CancellationToken token = default)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (predicate == null)
+                throw new ArgumentNullException(nameof(predicate));
+
+            token.ThrowIfCancellationRequested();
+
+            await foreach (var item in source.ConfigureAwait(false))
+            {
+                token.ThrowIfCancellationRequested();
+
+                if (predicate(item))
+                {
+                    return item;
+                }
+            }
+
+            return default;
+        }
+    }
+}
diff --git a/sdk/resourcemanager/Azure.ResourceManager.Core/src/ResourceOperationsBase.cs b/sdk/resourcemanager/Azure.ResourceManager.Core/src/ResourceOperationsBase.cs
index b7f628c27e68b..429da52c7e4e2 100644
--- a/sdk/resourcemanager/Azure.ResourceManager.Core/src/ResourceOperationsBase.cs
+++ b/sdk/resourcemanager/Azure.ResourceManager.Core/src/ResourceOperationsBase.cs
@@ -7,6 +7,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Azure.Core;
+using Azure.ResourceManager.Core.Extensions;
 
 namespace Azure.ResourceManager.Core
 {