All phone call (outbound & inbound) will throw events during their lifetime. Here is the expected cycle of a phone call:

1. requesting (event thrown only for outbound call)
2. trying (event thrown only for outbound call)
3. early (event thrown only for outbound call)
4. ringing
5. answering
6. active (peers are able to talk)
7. x call can changes states multiple time (hold, unhold, ...)
8. hangup (call stops and peers are not able to talk anymore)
9. purge (event is going to be destroy)
10. event is destroyed