Merge branch 'master' of https://github.com/cdjingit/brpc

fix conflict

docs/cn/client.md

@@ -137,7 +137,7 @@ int main() {
     brpc::ChannelOptions options;
     options.ns_filter = &my_filter;
     ...
-}dd
+}
 ```
 
 ## 负载均衡