Created by: gongweibao

To avoid multi servers binding to the same port(zombie process or parallel distribute training unit tests). https://serverfault.com/questions/329845/how-to-forcibly-close-a-socket-in-time-wait https://github.com/grpc/grpc/blob/f3c48495d5413d4e98b0dfc237145e8e7ce35842/src/core/lib/iomgr/tcp_server_utils_posix_common.cc#L167 https://stackoverflow.com/questions/14388706/how-do-so-reuseaddr-and-so-reuseport-differ https://eklitzke.org/binding-on-port-zero