Review incubator-shenyu-client-golang #19 PR

[Lisandro]

Dear community:

 The  incubator-shenyu-client-golang has new  pr,please review the code.Here is 
this pr main function: Design sdk_client_interface
rename zk_client

Here is link 
https://github.com/apache/incubator-shenyu-client-golang/pull/19/files