Add the possibility to await sync events (publishAwait)

[ziadalzarka]

I ran into an issue where I want to trigger an event that I don't want my code to continue to execute before it is processed, but it's not a synchronous event.

I'm suggesting adding a new publishAwait method that makes the publish method use async/await and await the deliver function.

[mroderick]

publishSync is synchronous, execution of the calling function will not continue until the event has been propagated.

I don't understand what you're suggesting this new publishAwait method would do, that can't be accomplished with the existing methods.

[ziadalzarka]

I modified the code in PR. It will execute code using async/await, publishSync doesn't wait for promises and publishAsync doesn't either. Do you understand what I mean?

[enersis-pst]

im also interesting in exact this functionality to wait for a subject.
other event listerns doesnt need for me to wait of this subject. but the whole process needs to be finished after all subjects are finished.