A SendAcknowledgementHandler notifies a client when an message sent asynchronously has been
received by the server.
If the session is not blocking when sending durable or non-durable messages, the session can set
a SendAcknowledgementHandler to be notified later when the messages has been received by the
server. The method
#sendAcknowledged(Message) will be called with the message that was
sent asynchronously.
The rate of notification can be controlled through
ServerLocator#setConfirmationWindowSize(int).
Notice that this notification will only take place if
ConfirmationWindowSize is set to a
positive value at
ServerLocator#setConfirmationWindowSize(int).