cb87246d47
The default executor for sending messages from the IMAP IDLE channel adapter is a single threaded thread pool. If the default executor is used (no executor injected), shut it down when the adapter is stopped. INT-2820 Polishing If using the default sendingTaskExecutor, create a new one when restarted. Add test to restart adapter after stop. INT-2820 Polishing Review comments; protect for null sendingTaskExecutor.