When running the python server, it will check the `SERVING_BIN` environment variable. If you want to use your own compiled binary file, set the environment variable to the path of the corresponding binary file, usually`export SERVING_BIN=${BUILD_DIR}/core/general-server/serving`.
BUILD_DIR is the absolute path of server build CPU or server build GPU。
BUILD_DIR is the absolute path of server build CPU or server build GPU。
for example: cd server-build-cpu && export SERVING_BIN=${PWD}/core/general-server/serving
