// The cast is safe because of the `run` and `error` checks.
      afterRanInterruptiblySuccess(uncheckedCastNullableTToT(result));
    } else {
      afterRanInterruptiblyFailure(error);
    }
  }

  abstract boolean isDone();

  abstract T runInterruptibly() throws Exception;

  abstract void afterRanInterruptiblySuccess(T result);

  abstract void afterRanInterruptiblyFailure(Throwable error);

          boolean isDone() {
            return false;
          }

          @Override
          String toPendingString() {
            return "";
          }

          @Override
          void afterRanInterruptiblySuccess(String result) {
            taskResult.set(result);
          }

          @Override
          void afterRanInterruptiblyFailure(Throwable error) {
            taskResult.setException(error);
          }