code: protected static function buildHttpClient04(
          LoopInterface $loop,
          $dns = null
      ) {
          // create dns resolver if one isn't provided
          if (null === $dns) {
              $dns = static::buildDnsResolver($loop);
          }
  
          // validate connector instance for proper error reporting
          if (!$dns instanceof DnsResolver) {
              throw new \InvalidArgumentException('For react http client v0.4, $dns must be an instance of DnsResolver');
          }
  
          $factory = new HttpClientFactory();
  
          return $factory->create($loop, $dns);
      }
docs: Builds a React Http client v0.4 style.
  
  @param LoopInterface    $loop
  @param DnsResolver|null $dns
  
  @return HttpClient