code: public function getContents()
      {
          if (is_null($this->stream) || ! $this->isReadable()) {
              $message = 'Could not get contents of stream';
  
              throw new \RuntimeException($message);
          }
  
          return stream_get_contents($this->stream);
      }
docs: Returns the remaining contents in a string
  
  @return string
  
  @throws \RuntimeException