[RPC] Make the port reusable after the socket is closed. (#2418)

* reuse.

* fix compile.
Co-authored-by: Ubuntu <ubuntu@ip-172-31-2-202.us-west-1.compute.internal>

src/rpc/network/tcp_socket.cc

@@ -30,6 +30,13 @@ TCPSocket::TCPSocket() {
   if (socket_ < 0) {
     LOG(FATAL) << "Can't create new socket. Errno=" << errno;
   }
+#ifndef _WIN32
+  // This is to make sure the same port can be reused right after the socket is closed.
+  int enable = 1;
+  if (setsockopt(socket_, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0) {
+    LOG(WARNING) << "cannot make the socket reusable. Errno=" << errno;
+  }
+#endif  // _WIN32
 }
 
 TCPSocket::~TCPSocket() {