added Clear to connection pool.
handled exceptions in background task of connection pool size maintenance.
moved heartbeat connection opening into try block.
catching connection exceptions in server in order to respond quicker to potential server down-time.
The overloaded async methods in Server's private ServerConnection class need to await the wrapped methods in order to actually catch the exceptions.
AsyncDropbox only needs to store one message per Id.
Run the heartbeat task exactly every "x" seconds.
Remove WaitAsync from AsyncMetronome class and rename class to Metronome.
Added AddressFamily to ServerSettings.
Propagate exceptions in BinaryConnection to pending sends and receives.
Added tests for exception propagation from BinaryConnection.
Renamed GetAwaiters to RemoveAllAwaiters and the method now removes the awaiters as well as returning them.