code: public function read(CompositeConnectionInterface $connection)
      {
          $header = $connection->readLine();
  
          if ($header === '') {
              $this->onProtocolError($connection, 'Unexpected empty reponse header');
          }
  
          $prefix = $header[0];
  
          if (!isset($this->handlers[$prefix])) {
              $this->onProtocolError($connection, "Unknown response prefix: '$prefix'");
          }
  
          $payload = $this->handlers[$prefix]->handle($connection, substr($header, 1));
  
          return $payload;
      }
docs: {@inheritdoc}