DBZ-604 Making sure connector cleanly shuts down also if records are …

[gunnarmorling]

…produced after polling loop has stopped

https://issues.jboss.org/projects/DBZ/issues/DBZ-604

@jpechane, can you check out this one?

[jpechane]

@gunnarmorling Applied, thanks!

[gabrywu]

Even if we clean the BlockingQueue,in some case before client disconnecting, the BlockingQueue still becomes full because of the enqueueRecord methord.

In our production ,the blocked still reprouce, but is a small probability event.
We fix it through the code

if( !stopping ){
                this.records.put(record);
            }else{
                logger.warn("Enqueue record while stopping: {}",record);
            }

https://issues.jboss.org/projects/DBZ/issues/DBZ-604