T - the type of the outcome objectpublic interface SuccessPromise<T>
Ratpack promises are not fully featured A+ promises. They are designed to be low level and adapted to more fully features asynchronous composition libraries (like RxJava, for which there is a Ratpack extension library).
Ratpack promises are not thread safe. Instances should not be used concurrently.
Async operations will typically return the subclass of the SuccessPromise, the Promise which allows an error handling strategy to be specified.
@NonBlocking void then(Action<? super T> then)
then - the action to forward the promised object on to