code: public Task<Void> continueWhile(Callable<Boolean> predicate,
        Continuation<Void, Task<Void>> continuation, CancellationToken ct) {
      return continueWhile(predicate, continuation, IMMEDIATE_EXECUTOR, ct);
    }
docs: Continues a task with the equivalent of a Task-based while loop, where the body of the loop is
  a task continuation.