message: Fix test (delref).
diff: @@ -15,6 +15,7 @@ Co::set([
  file_put_contents(TEST_LOG_FILE, '');
  swoole_async_write(TEST_LOG_FILE, $content[] = get_safe_random(), -1);
  swoole_async_write(TEST_LOG_FILE, $content[] = get_safe_random(), -1);
  +// return false bug can not close fd anymore
  swoole_async_write(TEST_LOG_FILE, $content[] = get_safe_random(), -1, function () { return false; });
  swoole_event_wait();
  $real_content = file_get_contents(TEST_LOG_FILE);
  @@ -25,4 +26,4 @@ assert($real_content === implode('', $content));
  [%s] TRACE zif_swoole_async_write(:%d): open write file fd#%d
  [%s] TRACE zif_swoole_async_write(:%d): reuse write file fd#%d
  [%s] TRACE zif_swoole_async_write(:%d): reuse write file fd#%d
  -[%s] TRACE aio_onFileCompleted(:%d): close file fd#%d
  +[%s] TRACE aio_onFileCompleted(:412): delref file fd#%d, refcount=%d
  