* fix bug
* optimiz
* update grpc_server_example
* add test cases
* fix: test case
* fix: test case
* return val directly
* fix: test case respond body compare text
* fix test case error
Co-authored-by: Wen Ming <moonbingbing@gmail.com>
* test: using `httpbin.org` for test cases.
* doc: add doc
* remove golang apt repository and runtime in travis.
* download proto file
Co-authored-by: Yuansheng <membphis@gmail.com>