connect method
Establishes connection to the server.
Usually all event listeners should be already attached when this method is invoked.
Returns a Future which resolves when the first connection attempt is carried out. However, note that connection may not always succeed on the first attempt — for state changes, do rely on the InboxReadyEvent and InboxUpdatedEvent events instead.
Implementation
Future<PushResponse> connect() {
if (_connectHasBeenCalled != false) {
throw StateError(
"This Inbox instance's .connect() method has already been called once.");
}
_connectHasBeenCalled = true;
return _setUpChannel();
}