anchor.diff:          }) as Callback1);
       stateB.onFuture(
           new Future.delayed(new Duration(milliseconds: 1)),
  -        expectAsync((value) {
  +        expectAsync1((value) {
             expect(log, ['a']);
             expect(value, isNull);
           }) as Callback1);
  
positive.code: 
      stateA.onTimeout(
          new Duration(milliseconds: 10),
          expectAsync(() {
            expect(machine.current, stateA);
            stateB.enter();
          }) as Callback0);
  
negative.code:         () => fail('should never be called'));
      stateB.onTimeout(
          new Duration(milliseconds: 10),
          expectAsync0(() {
            expect(machine.current, stateB);
            stateC.enter();
          }) as Callback0);
  