logger.warn("Failed to generate thumbnails.", e);
            resultBuf.append(e.getMessage()).append("\n");
        } finally {
            if (timeoutTask != null && !timeoutTask.isCanceled()) {
                timeoutTask.cancel();
            }
        }

        return resultBuf.toString();

    }

    protected void executeThumbnailGenerator() {

            return getResponseData(uri, includeContent);
        } finally {
            if (accessTimeoutTarget != null) {
                accessTimeoutTarget.stop();
                if (!accessTimeoutTask.isCanceled()) {
                    accessTimeoutTask.cancel();
                }
            }
        }
    }

    protected ResponseData getResponseData(final String uri, final boolean includeContent) {

    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());
    assertThrows(TimeoutException.class, () -> future.get(0, MILLISECONDS));
    nested.set("foo");
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    assertEquals("foo", future.get());
  }

  private static class Foo {}

    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());
    assertThrows(TimeoutException.class, () -> future.get(0, MILLISECONDS));
    nested.set("foo");
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    assertEquals("foo", future.get());
  }

  private static class Foo {}

    assertEquals(expectedValue, future.get());
  }

  public void testCancelledFuture() throws InterruptedException, ExecutionException {
    assertTrue(future.isDone());
    assertTrue(future.isCancelled());

    assertTrue(latch.await(5, SECONDS));
    assertTrue(future.isDone());
    assertTrue(future.isCancelled());

    assertThrows(CancellationException.class, () -> future.get());
  }

    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

  }

  public void testFutureCancelBeforeInputCompletion() throws Exception {
    assertTrue(resultFuture.cancel(true));
    assertTrue(resultFuture.isCancelled());
    assertTrue(inputFuture.isCancelled());
    assertFalse(outputFuture.isCancelled());
    assertThrows(CancellationException.class, () -> resultFuture.get());
  }

  public void testFutureCancellableBeforeOutputCompletion() throws Exception {

  }

  public void testFutureCancelBeforeInputCompletion() throws Exception {
    assertTrue(resultFuture.cancel(true));
    assertTrue(resultFuture.isCancelled());
    assertTrue(inputFuture.isCancelled());
    assertFalse(outputFuture.isCancelled());
    assertThrows(CancellationException.class, () -> resultFuture.get());
  }

  public void testFutureCancellableBeforeOutputCompletion() throws Exception {

    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    assertTrue(task.isDone());
    assertFalse(task.isCancelled());
    assertEquals(2, getDone(task).intValue());
  }

  public void testCancelled() throws Exception {
    TrustedListenableFutureTask<Integer> task = TrustedListenableFutureTask.create(returning(2));
    assertFalse(task.isDone());
    task.cancel(false);
    assertTrue(task.isDone());
    assertTrue(task.isCancelled());
    assertFalse(task.wasInterrupted());