leave method
Implementation
Future<void> leave() async {
await removeMemberStateEvent();
await backend.dispose(this);
setState(GroupCallState.localCallFeedUninitialized);
voip.currentGroupCID = null;
_participants.clear();
voip.groupCalls.remove(VoipId(roomId: room.id, callId: groupCallId));
await voip.delegate.handleGroupCallEnded(this);
_resendMemberStateEventTimer?.cancel();
setState(GroupCallState.ended);
}