Proto commits in smallnest/rpcx

These 12 commits are when the Protocol Buffers files have changed:

Commit:cf32df4
Author:chengy

fix issue #855

The documentation is generated from this commit.

Commit:3ceb230
Author:chengy

fix issues #855

Commit:57879dd
Author:xusworld

feat (package codec): rename test_data dir to testdata ase enter the commit message for your changes. Lines starting

Commit:1b65660
Author:xusworld
Committer:xusworld

feat (package protocol): add benchmark test 1. add snappy compressor 2. add compressor benchmark

Commit:7923858
Author:lukedong
Committer:lukedong

dev: unit test for package codec

Commit:f0d415b
Author:lukedong

dev: unit test for package codec

Commit:402c957
Author:smallnest

add server plugins feature and add zookeeper/etcd/consul registries

Commit:8eb4b17
Author:smallnest

add messagepack and protobuf tests

Commit:c1815c2
Author:smallnest

removed examples and benchmarks because they are moved to rpcx-ecosystem

Commit:1745f12
Author:smallnest

add gRPC benchmark code and test results

Commit:940ccbd
Author:smallnest

add benchmark code

Commit:0ba1a43
Author:smallnest

add protobuf ServerCodec and ClientCodec