title: Can't set Guzzle Content Type
body: <p>I'm trying to request this way:</p>
  
  <pre><code>$body = [];
  $body['holder_name'] = $full_name;
  $body['bank_code'] = $bank_number;
  $body['routing_number'] = $branch_number;
  $body['account_number'] = $account_number;
  $body['type'] = 'checking';
  
  $client = new GuzzleHttp\Client([
  'base_url' =&gt; [$url, []],
  'headers'  =&gt; ['content-type' =&gt; 'application/json', 'Accept' =&gt; 'application/json'],
      'defaults' =&gt; [
           'auth' =&gt; [$publishable_key, ''],
  ],
      'body' =&gt; json_encode($body),
  ]);
  </code></pre>
  
  <p>The problem is that this request is being set without Content-Type.
  What am I doing wrong?</p>