reconnect method
Enforces to reconnect with the incoming service.
Also compare disconnect. Also compare connect.
Implementation
Future<void> reconnect() async {
await _incomingLock.synchronized(() => _incomingMailClient.disconnect());
// the reconnect loop must not run under the incoming lock: it retries
// until disconnect() is called, which needs the lock as well, and it
// lists the mailboxes through this client when required
await _incomingMailClient.reconnect();
_isConnected = true;
}