E x = items[takeIndex];
    items[takeIndex] = null;
    takeIndex = inc(takeIndex);
    --count;
    return x;
  }

  /**
   * Utility for remove and iterator.remove: Delete item at position i. Call only when occupying
   * monitor.
   */
  void removeAt(int i) {
    final E[] items = this.items;
    // if removing front item, just advance
    if (i == takeIndex) {
      items[takeIndex] = null;

      }
    }
  }

  private void compareResultsForThisListOfStimuli() {
    int removes = Collections.frequency(Arrays.asList(stimuli), remove);
    if ((!features.contains(IteratorFeature.SUPPORTS_REMOVE) && removes > 1)
        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack

  }

  // retainAll(empty)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmpty() {
    expectReturnsFalse(empty);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmptyUnsupported() {

  @Override
  @CheckForNull
  public V remove(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    if ((rowKey == null) || (columnKey == null)) {
      return null;
    }
    Map<C, V> map = safeGet(backingMap, rowKey);
    if (map == null) {
      return null;
    }
    V value = map.remove(columnKey);
    if (map.isEmpty()) {
      backingMap.remove(rowKey);
    }
    return value;
  }

   * removeFrom.removeIf(predicate)} instead.
   *
   * @param removeFrom the iterable to (potentially) remove elements from
   * @param predicate a predicate that determines whether an element should be removed
   * @return {@code true} if any elements were removed from the iterable
   * @throws UnsupportedOperationException if the iterable does not support {@code remove()}.
   * @since 2.0
   */

    assertEquals((Integer) 2, it.next());
    it.remove();
    // After this remove, 400 has moved up and 20 down past cursor
    assertTrue("Heap is not intact after remove", mmHeap.isIntact());
    assertEquals((Integer) 10, it.next());
    assertEquals((Integer) 3, it.next());
    it.remove();
    // After this remove, 400 moved down again and 500 up past the cursor

  }

  // retainAll(empty)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmpty() {
    expectReturnsFalse(empty);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRetainAll_emptyPreviouslyEmptyUnsupported() {

    assertEquals((Integer) 2, it.next());
    it.remove();
    // After this remove, 400 has moved up and 20 down past cursor
    assertTrue("Heap is not intact after remove", mmHeap.isIntact());
    assertEquals((Integer) 10, it.next());
    assertEquals((Integer) 3, it.next());
    it.remove();
    // After this remove, 400 moved down again and 500 up past the cursor

      iterator.remove();
      assertEquals(initialSize - 1, map.size());

      // Use "entryCopy" instead of "entry" because "entry" might be invalidated after
      // iterator.remove().
      assertFalse(entrySet.contains(entryCopy));
      assertInvariants(map);
      try {
        iterator.remove();
        fail("Expected IllegalStateException.");

        return removeSnapshot!!
      }

      override fun remove() {
        val removeSnapshot = this.removeSnapshot
        checkNotNull(removeSnapshot) { "remove() before next()" }
        try {
          this@DiskLruCache.remove(removeSnapshot.key())
        } catch (_: IOException) {
          // Nothing useful to do here. We failed to remove from the cache. Most likely that's