* add TracerUtil
* Interceptor ok
* add handler
* add context
* minor update
* keep span in trace context
* add span in search okay
* Update Context.cpp
* refactor
* refactor
* refactor
* format
* add context in SearchJob
* trace search okay
* add back finish span in interceptor
* add namespace
* add tracing config in server config
* add random id
* debug mode okay
* update CMakeLists
* add opentracing to cmake
* update unittest
* add tracing namespace
* remove std::run_time error
* add lock when erasing context_map
* update tracing config
* lint
* update CHANGELOG
* small fix
* fix server unit test
* fix scheduler unit test
* fix db unit test
* lint
* fix db unit test gpu version
* rename to tracing_config
* fix
* update
* trigger ci
