Retrieves the initial sequence from which this ReliableMessageListener should start.
Return -1 if there is no initial sequence and you want to start from the next published message.
If you intent to create a durable subscriber so you continue from where you stopped the previous
time, load the previous sequence and add 1. If you don't add one, then you will be receiving the
same message twice.
Checks if this ReliableMessageListener is able to deal with message loss. Even though the reliable topic promises to
be reliable, it can be that a MessageListener is too slow. Eventually the message won't be available anymore.
If the ReliableMessageListener is not loss tolerant and the topic detects that there are missing messages, it will
terminate the ReliableMessageListener.
Invoked when a message is received for the added topic. Note that topic guarantees message ordering.
Therefore there is only one thread invoking onMessage. The user should not keep the thread busy, but preferably
should dispatch it via an Executor. This will increase the performance of the topic.