ClosingFuture<String> closingFuture = ClosingFuture.from(immediateFuture("value1"));
    FluentFuture<String> unused = closingFuture.finishToFuture();
    assertDerivingThrowsIllegalStateException(closingFuture);
  }

  @Override
  <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException {
    return getUninterruptibly(closingFuture.finishToFuture());
  }

  @Override