GuzzleHttp\Client::send PHP Method

    public function send(RequestInterface $request, array $options = [])
    {
        $options[RequestOptions::SYNCHRONOUS] = true;
        return $this->sendAsync($request, $options)->wait();
    }

 /**
  * @return array
  */
 public function doRequest() : array
 {
     $this->generateRequestOptions();
     $this->authenticator->authenticate($this);
     $request = $this->httpClient->createRequest($this->method, $this->getUrl(), $this->requestOptions);
     return $this->httpClient->send($request)->json();
 }