Only write missing parts.

prrt/time-protocol.h

@@ -113,7 +113,7 @@ static inline ssize_t _send(socket_t conn, const char *buf, size_t size)
     int written = 0;
     ssize_t n = 0;
     while (written < size) {
-        n = write(conn, buf, size);
+        n = write(conn, buf, size - written);
         if (n < 0) {
             _time();
             printf("WRITE FAILED: %ld, errno: %d\n", n, errno);