this.rowKey = checkNotNull(rowKey);
    }

    @Nullable Map<C, V> backingRowMap;

    final void updateBackingRowMapField() {
      if (backingRowMap == null || (backingRowMap.isEmpty() && backingMap.containsKey(rowKey))) {
        backingRowMap = computeBackingRowMap();
      }
    }

    @Nullable Map<C, V> computeBackingRowMap() {
      return backingMap.get(rowKey);
    }

     *            element whose presence in this set is to be tested.
     * @return true if this set contains the specified element.
     */
    @Override
    public boolean contains(final Object o) {
        return map.containsKey(o);
    }

    /**
     * Adds the specified element to this set if it is not already present.
     *
     * @param o
     *            element to be added to this set.

        map2.put("key3", "value3");
        event.setSourceMap(map2);
        assertEquals(2, event.toSource().size());
        assertFalse(event.toSource().containsKey("key1"));
        assertTrue(event.toSource().containsKey("key2"));
        assertTrue(event.toSource().containsKey("key3"));
    }

    Object one = new Object();
    assertNull(map.put(one, one));
    assertSame(one, map.get(one));
    assertTrue(map.containsKey(one));
    assertTrue(map.containsValue(one));
    Object two = new Object();
    assertSame(one, map.replace(one, two));
    assertTrue(map.containsKey(one));
    assertFalse(map.containsValue(one));
    Object three = new Object();
    assertTrue(map.replace(one, two, three));

    segment.setTableEntryForTesting(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    // don't see absent values now that count > 0

    segment.setTableEntryForTesting(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    // don't see absent values now that count > 0

  }

  @Override
  public boolean containsEntry(@Nullable Object key, @Nullable Object value) {
    return delegate().containsEntry(key, value);
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return delegate().containsKey(key);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return delegate().containsValue(value);
  }

  @Override

  }

  @Override
  public boolean containsEntry(@Nullable Object key, @Nullable Object value) {
    return delegate().containsEntry(key, value);
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return delegate().containsKey(key);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return delegate().containsValue(value);
  }

  @Override

      List<Entry<Object, Object>> warmed = warmUp(cache);
      for (int i = WARMUP_MIN; i < WARMUP_MAX; i++) {
        Entry<Object, Object> entry = warmed.get(i - WARMUP_MIN);
        assertTrue(cache.asMap().containsKey(entry.getKey()));
        assertTrue(cache.asMap().containsValue(entry.getValue()));
        // this getUnchecked() call shouldn't be a cache miss; verified below

    assertFalse(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertEmpty(result);

    assertTrue(result.add(v1()));
    assertTrue(result.add(v2()));

    assertContentsAnyOrder(result, v1(), v2());
    assertContentsAnyOrder(multimap().get(k0()), v1(), v2());
    assertTrue(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));