d6e600548b
Motivation: Http2FrameStream#CONNECTION_STREAM is required to identify the connection stream. However this leads to inconsistent usage from a user perspective. When a user creates a Http2Frame for a non-connection stream, the Http2MultiplexCodec automatically sets the stream, and the user is never exposed to the Http2FrameStream object. However when the user writes a Http2Frame for a connection stream they are required to set the Http2FrameStream object. We can remove the Http2FrameStream#CONNECTION_STREAM and keep the Http2FrameStream object internal, and therefore consistent between the connection and non-connection use cases. Modifications: - Remove Http2FrameStream#CONNECTION_STREAM - Update Http2FrameCodec to handle Http2Frame#stream() which returns null Result: More consistent usage on http2 parent channel and http2 child channel.