message: Add check for double uv_close
diff: @@ -78,9 +78,12 @@ namespace asynchost
  friend class close_ptr;
  void close()
  + {
  + if (!uv_is_closing((uv_handle_t*)&uv_handle))
  {
  uv_close((uv_handle_t*)&uv_handle, on_close);
  }
  + }
  static void on_close(uv_handle_t* handle)
  {
  