final Tuple3<String, String, String> task = new Tuple3<>(getName(), thumbnailId, path);
        if (logger.isDebugEnabled()) {
            logger.debug("Create thumbnail task: {}", task);
        }
        return task;
    }

    /**
     * Sets the directory name length for thumbnail storage.

    }

    @Override
    public <T> Future<T> submit(Callable<T> task) {
      throw new UnsupportedOperationException();
    }

    @Override
    public Future<?> submit(Runnable task) {
      throw new UnsupportedOperationException();
    }

    @Override
    public <T> Future<T> submit(Runnable task, T result) {
      throw new UnsupportedOperationException();
    }

    @Override

## Context Managers { #context-managers }

     * Destroys this thumbnail generator and releases any resources.
     */
    void destroy();

    /**
     * Creates a thumbnail generation task.
     * @param path The path to the source document.
     * @param docMap The document map containing metadata.
     * @return A tuple containing task information.
     */
    Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap);

[2020-01-01 00:00:00] << 0x00000003     0 DATA          END_STREAM
[2020-01-01 00:00:00] << 0x00000000     8 GOAWAY
[2020-01-01 00:00:05] << 0x00000000     8 GOAWAY
```

### Task Runner Logging 

This logs task enqueues, starts, and finishes.

```
[2020-01-01 00:00:00] Q10000 scheduled after   0 µs: OkHttp ConnectionPool
[2020-01-01 00:00:00] Q10000 starting              : OkHttp ConnectionPool

    allTasks.add(setFutureCompleteExceptionallyRunnable);
    allTasks.add(setFutureCancelRunnable);
    for (int k = 0; k < 50; k++) {
      // For each listener we add a task that submits it to the executor directly for the blocking
      // get use case and another task that adds it as a listener to the future to exercise both
      // racing addListener calls and addListener calls completing after the future completes.

## Ask Questions { #ask-questions }

You can <a href="https://github.com/fastapi/fastapi/discussions/new?category=questions" class="external-link" target="_blank">create a new question</a> in the GitHub repository, for example to:

* Ask a **question** or ask about a **problem**.
* Suggest a new **feature**.

**Note**: if you do it, then I'm going to ask you to also help others. 😉

  private final ExecutionList executionList = new ExecutionList();

  /**
   * Creates a {@code ListenableFutureTask} that will upon running, execute the given {@code
   * Callable}.
   *
   * @param callable the callable task
   * @since 10.0
   */
  public static <V extends @Nullable Object> ListenableFutureTask<V> create(Callable<V> callable) {
    return new ListenableFutureTask<>(callable);
  }

  /**

   *
   * @throws RejectedExecutionException if the executor has been previously shutdown
   */
  private void startTask() {
    synchronized (lock) {
      if (shutdown) {
        throw new RejectedExecutionException("Executor already shutdown");
      }
      runningTasks++;
    }
  }

  /** Decrements the running task count. */
  private void endTask() {

Directory for log files of DBFlute tasks

If your execution of DBFlute task fails,