||An interface for a listener to be registered with the transport protocol,
typically so that a client can be notified of incoming connections, new data,
and so forth.
||A serialization interface for objects that are to be sent over the network by
some transport protocol.
||A handle to a
Message object either currently or previously
enqueued for delivery.
||A callback interface allowing a client to be notified when the state of a
||A queue of messages to be delivered to some destination.
||An interface through which the client can notify the transport protocol that
it is ready for processing a given