- When using the array pool, we get terrible block density and as a result
the header parser was failing.
- This fixes the case where the parser needed to skip 2 blocks at the end
(which is unrealistic). Comparing the current index to the reader index is incorrect
since we may end up at the same index in another segment.
- Most of the shared code is in the HttpProtocol class (former Frame)
- Virtual calls handle protocol-specific things
- Move the ProcessRequestsAsync loop to HttpProtocol
- Implement HTTP/1.x request processing in Http1Connection and HTTP/2
in Http2Stream, with Http1Connection<T> and Http2Stream<T> subclassing
those classes in order to handle the generic HttpContext parameter
- Split MessageBody into Http1MessageBody and Http2MessageBody,
with MessageBody containing shared member variables and methods