Motivation:
SocketException and ODE are being thrown when disconnecting gracefully.
Modifications:
- dismiss async read completion if it is done on inactive channel
- do not attempt sync-reading from a socket that is not Connected
- extra: fixing echo sample with better practices
- extra: ReadListener for more natural test scenarios
- extra: tweaked nbench spec to work in-loop
Result:
No excessive errors happen during graceful shutdown
