message: Optimzie type of return value
diff: @@ -243,7 +243,7 @@ _do_recv:
  */
  int Protocol::recv_with_eof_protocol(network::Socket *socket, String *buffer) {
  bool recv_again = false;
  - int buf_size;
  + size_t buf_size;
  RecvData rdata{};
  _recv_data:
  @@ -254,7 +254,7 @@ _recv_data:
  buf_size = SW_BUFFER_SIZE_STD;
  }
  - int n = socket->recv(buf_ptr, buf_size, 0);
  + ssize_t n = socket->recv(buf_ptr, buf_size, 0);
  if (n < 0) {
  switch (socket->catch_read_error(errno)) {
  case SW_ERROR:
  