title: Send image data over RTC Data Channel
body: <p>I am trying to send the image data over a <code>Data Channel</code>, but it is not working.
  When just getting the data from <code>ctx.getImageData</code>, I receive a string <code>"[Object ImageData]"</code> on the other side. Converting the data piece only to a blob results in an error: <code>Uncaught NetworkError: Failed to execute 'send' on 'RTCDataChannel': Could not send data</code>. I get the same error when trying to convert it to an <code>ArrayBuffer</code>. How should I do this?</p>