assertEquals(3, counter.getCount());
  }

  public void testSkip() throws IOException {
    assertEquals(10, counter.skip(10));
    assertEquals(10, counter.getCount());
  }

  public void testSkipEOF() throws IOException {
    assertEquals(20, counter.skip(30));
    assertEquals(20, counter.getCount());
    assertEquals(0, counter.skip(20));
    assertEquals(20, counter.getCount());

    assertEquals(3, counter.getCount());
  }

  public void testSkip() throws IOException {
    assertEquals(10, counter.skip(10));
    assertEquals(10, counter.getCount());
  }

  public void testSkipEOF() throws IOException {
    assertEquals(20, counter.skip(30));
    assertEquals(20, counter.getCount());
    assertEquals(0, counter.skip(20));
    assertEquals(20, counter.getCount());

    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    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());

    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(0);
    written += 1;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    byte[] data = new byte[10];
    counter.write(data);
    written += 10;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(data, 0, 5);
    written += 5;

    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(0);
    written += 1;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    byte[] data = new byte[10];
    counter.write(data);
    written += 10;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(data, 0, 5);
    written += 5;

     */
    @Override
    public boolean equals(@CheckForNull Object object) {
      if (object instanceof Multiset.Entry) {
        Multiset.Entry<?> that = (Multiset.Entry<?>) object;
        return this.getCount() == that.getCount()
            && Objects.equal(this.getElement(), that.getElement());
      }
      return false;
    }

    /**
     * Return this entry's hash code, following the behavior specified in {@link

    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    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());

    this.offset = offset;
    this.length = length;
  }

  private int getCount(int index) {
    return (int) (cumulativeCounts[offset + index + 1] - cumulativeCounts[offset + index]);
  }

  @Override
  Entry<E> getEntry(int index) {
    return Multisets.immutableEntry(elementSet.asList().get(index), getCount(index));
  }

  @Override
  @CheckForNull
  public Entry<E> firstEntry() {

    if (!entryIterator.hasNext()) {
      return null;
    }
    Entry<E> entry = entryIterator.next();
    return Multisets.immutableEntry(entry.getElement(), entry.getCount());
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return delegate().lastEntry();
  }

  /**
   * A sensible definition of {@link #lastEntry()} in terms of {@code

  private File file;

  /** ByteArrayOutputStream that exposes its internals. */
  private static class MemoryOutput extends ByteArrayOutputStream {
    byte[] getBuffer() {
      return buf;
    }

    int getCount() {
      return count;
    }
  }

  /** Returns the file holding the data (possibly null). */
  @VisibleForTesting
  @CheckForNull
  synchronized File getFile() {
    return file;
  }

  /**