title: How to add a callback to ipc renderer send
body: <p>Googling says you can add a callback to it, but the documentation just says "arg1, arg2, arg3" etc.</p>
  
  <p>They also have sendSync, but I'd prefer not to block while my event is being sent [we're trying to do as much work through the browser as possible, because writing client code in node, seems a little daft].</p>
  
  <p>If the creators have a sendSync, then surely they have a version with callbacks, or better yet promises.</p>
  
  <p>Some examples of things i'd like to be able to do:</p>
  
  <pre><code>//callback
  ipcRenderer.send('anaction', '[1, 2, 3]', function() { console.log('done anaction') });
  //promise
  ipcRenderer.send('anaction', '[1, 2, 3]')
      .then(function() { console.log('done anaction') });
  
  //sync exists, but it blocks. I'm looking for a non-blocking function
  ipcRenderer.sendSync('anacount', '[1, 2, 3]')
  console.log('done anaction');
  </code></pre>