class lime.app.Future<T>

var isCompleted:Bool

var value:T

function new(?work:Void ->T): Void

function onComplete(listener:T ->Void): Future<T>

function onError(listener:Dynamic ->Void): Future<T>

function onProgress(listener:Float ->Void): Future<T>

function then<U>(next:T ->Future<U>): Future<U>