Fix non-terminating sender.

sender.c

@@ -34,10 +34,8 @@ int main(int argc, char* const argv) {
         sprintf(buf, "this is a message %d", i);
         prrt_send(&sock, buf, strlen(buf));
     }
-
-    usleep(5000*1000);
+    usleep(1000*1000);
     prrt_close_socket(&sock);
-    pthread_exit(NULL);
-
+    printf("COMPLETELY CLOSED\n");
     return 0;
 }