fix event lost

[ningmingxiao]

sometimes if listener chan is full,event will lost. @fsouza @bufdev can you review my pr? thank you

[bufdev]

@ningmingxiao I have not been involved in this repo for about a decade, it's not really professional to tag people here. Will leave this to others.

[ningmingxiao]

sory,but thank you anyway.

[fsouza]

Thanks for contributing! This is a big change that can lead to slow consumers hanging. I recommend either making sure your caller is always fast enough to consume the events, or putting the new behavior behind a knob.

[ningmingxiao]

sometimes I can't make sure consumers run faster, if run plenty of containers, will generate many events, channel will be filled. At least we should let user know event is dropped when chan is filled.

[fsouza]

Can you add a knob in that case?

[ningmingxiao]

Can you add a knob in that case?

Could you describe it in more detail? Thank you

[fsouza]

@ningmingxiao I imagine we'd have a new option when adding the listener. Internally the listener would become some struct with the channel + some listening options, and externally we'd probably need to have versions of AddEventListenerWithOptions and RemoveEventListener that take a struct with "listening options" instead of just the channel.