Motivation

During the implementation of the new S3 provider, we noticed that Response.close is never called on the werkzeug response, and therefore not propagated to other underlying objects. The test I added worked when serving it directly through the werkzeug server, and I found it's calling close here, where application_iter is the Response object.

We actually had no analogous call in our ASGI/WSGI bridge, so this PR adds that.

Changes

• Encapsulate the sync/async iterable wrapper into a class and propagate any calls to aclose to the underlying close method.

I was briefly worried that this may break test_chunked_transfer_encoding_client_timeout but seems to still work, so although aclose is overwritten, it propagates the GeneratorExit exception correctly 👍