Creates a future that runs its computation after a delay.
The computation will be executed after the given duration has passed,
and the future is completed with the result of the computation.
If computation returns a future,
the future returned by this constructor will complete with the value or
error of that future.
If the duration is 0 or less, it completes no sooner than in the next event-loop iteration, after all microtasks have run.
If computation is omitted,
it will be treated as if computation was () => null,
and the future will eventually complete with the null value.
If calling computation throws, the created future will complete with the
error.
See also Completer for a way to create and complete a future at a later time that isn't necessarily after a known fixed duration.
factory Future.delayed(Duration duration, [FutureOr<T> computation()]) {
_Future<T> result = new _Future<T>();
new Timer(duration, () {
if (computation == null) {
result._complete(null);
} else {
try {
result._complete(computation());
} catch (e, s) {
_completeWithErrorCallback(result, e, s);
}
}
});
return result;
}