Make OnConnectionStateChange wait for handler to finish

[sukunrt]

OnConnectionStateChange is used to determine whether the peer connection has succeeded and track connection state by users. It should be called in sync. Right now state changes might get reordered which would lead to tracking errors for users.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.38%. Comparing base (3f6d94a) to head (cbb2ae3).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2702      +/-   ##
==========================================
- Coverage   76.42%   76.38%   -0.04%     
==========================================
  Files          87       87              
  Lines        9934     9927       -7     
==========================================
- Hits         7592     7583       -9     
- Misses       1870     1871       +1     
- Partials      472      473       +1     

Flag	Coverage Δ
go	77.91% <100.00%> (-0.04%)	⬇️
wasm	64.57% <ø> (-0.09%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sukunrt]

I have moved the updates to a operations queue. That'll run the notifications sequentially. This ensures that users can do things like pc.Close from the call back.

[Sean-Der]

This was fixed by pion/ice@67cc918, going to close here!

Will be tagging a new version of pion/ice today! thank you @sukunrt :)

[sukunrt]

It's not exactly fixed. The state reported on the callback isn't reliable. Users need to ignore the state provided on the call back and call pc.ConnectionState() for the accurate state of the connection.