* Renames from API review
- Rename Microsoft.AspNetCore.Protocols.Abstractions to Microsoft.AspNetCore.Connections.Abstractions.
- Renamed IConnectionHandler to IConnectionDispatcher (and related properties and types)
- Added ConnectionHandler and UseConnectionHandler extension method to Connections.Abstractions.
- Use ActivatorUtilties to create the ConnectionHandler
- Based on the changes you made earlier (f4d27e6), we trigger OnConnectionClosed before the socket is disposed in the SocketTransport. This moves the call to Output.Complete to happen after and thus fixes the race.