title: android binding : Map java interface based callback to modern C#
body: <p>I'm fine-tuning a library written in java for android that deals with bluetooth, that I will use in a Xamarin project with native binding.
  Since it deal with I/O, most of the api contains async method and, cause we don't have access to the good stuff yet (lambdas), those async calls are dealt using callbacks (an interface to be implemented by the client). ie :</p>
  <pre><code>void connect(BluetoothPeripheral target, IConnectionCompletion handler);
  </code></pre>
  <p>Of course in C#, there are much better way to deal with async stuff : Action instead of creating a whole new class, or even better the Task with async/await.</p>
  <p>My question is : What do I need to do to map those Callback based java methods to C# methods that will return Task or take and Action instead of the callback?</p>