title: Guzzle 422 Unprocessable Entity error
body: <p>I'm using browserstack screenshots API - <a href="https://www.browserstack.com/screenshots/api" rel="nofollow">https://www.browserstack.com/screenshots/api</a> The following curl is working:</p>
  
  <pre><code>curl -u "username:password" -H "Content-Type: application/json" -H "Accept: application/json"  -d '{"browsers": [{"os": "Windows", "os_version": "7", "browser_version": "8.0", "browser": "ie"}], "url": "http://google.com"}' http://www.browserstack.com/screenshots
  </code></pre>
  
  <p>However, when I try the same call call with guzzle I get 422 Unprocessable Entity error. </p>
  
  <pre><code>$client = new GuzzleHttp\Client();
  $request = $client-&gt;post('http://www.browserstack.com/screenshots', [
          'headers' =&gt; ['Content-type' =&gt; 'application/json'],
          'auth' =&gt;  ['username', 'password']
  ]
  );
  
  $data = ['browsers' =&gt; ['os' =&gt; 'Windows', 'os_version' =&gt; '7', 'browser_version' =&gt; '8.0', 'browser' =&gt; 'ie'], 'url' =&gt; 'http://google.com'];
  $request-&gt;setBody($data);
  $response = $request-&gt;send();
  dd($response);
  </code></pre>
  
  <p>Can you suggest how to debug this issue?</p>