Feature-gated SdkBody and ByteStream creation upgrade guidance

[ysaito1001]

If you do not currently depend on any of the following:

• SdkBody::from_dyn
• impl From<hyper::Body> for SdkBody
• impl From<hyper::Body> for ByteStream

then you can stop reading this guide now since you won't be impacted by these changes.

This guide assumes that SdkBody and ByteStream have been moved to aws-smithy-types from aws-smithy-http (as a result of #3026).

Previously, the said methods publicly exposed third-party types of unstable crates. To anticipate the need for supporting equivalent functionality with 1.x of those crates in the future, we now feature-gate the exposed types so customers opt-in to use them, which then allows us to add support for 1.x of those crates in a backwards compatible fashion.

Upgrading SdkBody::from_dyn

Wherever SdkBody is created with from_dyn, you can turn on a cargo feature http-body-0-4-x within aws-smithy-types and use SdkBody::from_body_0_4 instead.

Upgrading impl From<hyper::Body> for SdkBody

• If you currently use SdkBody::from(hyper::Body) (or hyper::Body::into(self) -> SdkBody), then you can turn on a cargo feature http-body-0-4-x within aws-smithy-types and use SdkBody::from_body_0_4 instead.
• If you have a generic with a trait bound impl From<hyper::Body>, then you can turn on both http-body-0-4-x and hyper-0-14-x cargo features within aws-smithy-types to enable the From<hyper_0_14::Body> for SdkBody.

Upgrading impl From<hyper::Body> for ByteStream

• If you currently use ByteStream::from(hyper::Body) (or hyper::Body::into(self) -> ByteStream), then you can turn on a cargo feature http-body-0-4-x within aws-smithy-types and use ByteStream::from_body_0_4 instead.
• If you have a generic with a trait bound impl From<hyper::Body>, then you can turn on both http-body-0-4-x and hyper-0-14-x cargo features within aws-smithy-types to enable the From<hyper_0_14::Body> for ByteStream.

Recommended practice

Most importantly, if you generate the SDK for a service, ByteStream and SdkBody are reexported from a module called primitives. You should use those reexported ones instead of directly using them from aws-smithy-types.