* Add `RotatingServerAdvice.StandardRotationPolicy.getCurrent()` method for better end-user experience when this class is extended * Add NPE protection into the MQTT Channel Adapters. Some code style polishing for them **Cherry-pick to 5.0.x**
* Add `RotatingServerAdvice.StandardRotationPolicy.getCurrent()` method for better end-user experience when this class is extended * Add NPE protection into the MQTT Channel Adapters. Some code style polishing for them **Cherry-pick to 5.0.x**