- This change aims to clean up the feature interfaces
used by kestrel and exposed by protocol absractions. It splits out the
IConnectionTransportFeature into smaller features that may or may
not be implemented on the connection.
- Added all of the features from Socket.Abstractions
in an attempt to make it go away completely. As a result
the helper methods and extensions have all been added here.
- Change IConnectionHandler to take TransportConnection. This cleans up the interface and makes it more explicit what features are required by Kestrel
