Netty4

Warning

1. If provider need to use different communication layer framework for different protocols , please configure multiple protocols separately.

2. consumer configuration as follow：

   <dubbo:consumer client="netty">
       <dubbo:reference />
   </dubbo:consumer>
   

   <dubbo:consumer client="netty4">
       <dubbo:reference />
   </dubbo:consumer>
   

Next we will continue to do something：We will provide a reference data on the performance test indicators and performance test comparison with the version of netty 3.