See https://github.com/jclouds/jclouds/commit/c49489afc8d3e910067469bf62bc9f335db64825 for an alternative approach. This changes the method signature but is a smaller change overall.

Pity we can't get the method _back_ from the [`Invokable`](http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/reflect/Invokable.html). If we want to leave the method sig the same we *could* create some kind of "MethodExposingInvokable", though..?