the patch to improve mysql open replicator event producer's performance

[andyqzb]

I want to make a patch to improve the mysql open replicator event producer's performance.

The design is very simple. The binlog parser just put the binlog event to a queue and return immediately. Then another thread fetch binlog event from the queue, and transform it to databus event, put the event into databus buffer.

Under the patch, the process of the binlog divide into two parts. So I think it can improve the performance greatly.