add TimeOutMessage event

[phuongdinh1411]

Hi @deruelle @brainslog , Can you please review the implementation for me?
Thank you so much for recommending me this issue.

[deruelle]

Thanks @phuongdinh1411. @brainslog can you review ?

[brainslog]

Hi @phuongdinh1411, thanks for this contribution.

I am not sure this is the best approach, it doesn't work fully for me, can you tell me how have you tested ?

In my understanding the best option would be to try to standardize the stack on the org.jdiameter.api.EventListener.timeoutExpired(Request) method, to deliver the timeout message to the context, eg: in case of the ClientAcc, it sends an event of type FAILED_SEND_RECORD and after that calls the context.failedSendRecord method on the context (which would be the RA)

This likely might need to be discussed and customized on a application basis, otherwise we'll have multiple callbacks, because other diameter apps have higher level callbacks (eg: Client CCA), others move to a TIMED_OUT state (eg: S6a), etc...

Thoughts ?