Merge into master from pull request #3545:

...main/java/net/floodlightcontroller/core/OFSwitchBase.java

...va/net/floodlightcontroller/core/internal/Controller.java

...oodlightcontroller/debugcounter/IDebugCounterService.java

.../java/net/floodlightcontroller/debugevent/DebugEvent.java

src/main/java/net/floodlightcontroller/debugevent/Event.java

...t/floodlightcontroller/debugevent/IDebugEventService.java

...va/net/floodlightcontroller/debugevent/IEventUpdater.java

...a/net/floodlightcontroller/debugevent/NullDebugEvent.java

...ntroller/linkdiscovery/internal/LinkDiscoveryManager.java

...a/net/floodlightcontroller/debugevent/DebugEventTest.java

...t/java/net/floodlightcontroller/debugevent/EventTest.java