message: fix read_eof bug
diff: @@ -777,11 +777,11 @@ swString* swoole_sync_readfile_eof(int fd)
  }
  else
  {
  - if (swString_extend(data, data->size * 2) < 0)
  + data->length += n;
  + if (data->length == data->size && swString_extend(data, data->size * 2) < 0)
  {
  return data;
  }
  - data->length += n;
  }
  }
  return data;
  