title: Ask Twilio to pass custom headers in webhooks
body: <p>I'm using Twilio REST Api to create a call programmatically, with call-status and recordings web-hooks wired in. The web-hook POST requests are currently hitting the server but failing on me because there is a requirement for a custom header entry.</p>
  <p>I want to be able to pass my custom headers (that needs to be sent in the upcoming web-hook request headers) when I create those calls with the web-hook urls. The custom header should have <code>dynamic</code> value.</p>
  <p>I have something like this:</p>
  <pre><code>call = @client.calls.create(
            to: &quot;+1XYZ&quot;,
            from: ENV['TWILIO_ACCESS_NUMBER'],
            twiml: '&lt;Response&gt;&lt;Record /&gt;&lt;/Response&gt;', 
            status_callback: @@callStatusHandler,
            status_callback_event: ['answered', 'completed'],
          )
  </code></pre>
  <p>When I create such calls, I will have access to <code>sessionid</code> with a dynamic value, say <code>my-session-value</code>. Now when the webhook request comes in, I want <code>sessionid = my-session-value</code> in the header.</p>
  <p>Is there a way to achieve this?</p>