@Nonnull
    static <U> Promise<U> supplyingExceptionallyAsync(@Nonnull Callable<U> callable) {
        Promise<U> p = empty();
        return p.supplyExceptionallyAsync(callable);
    }
Returns a new Promise, and schedules it's population via the given callable.

@param callable the value callable
@param <U> the result type
@return the promise
helper/src/main/java/me/lucko/helper/promise/Promise.java