}
      return false;
    }

    @Override
    public boolean remove(@Nullable Object o) {
      if (o instanceof Map.Entry) {
        Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
        return multimap().remove(entry.getKey(), entry.getValue());
      }
      return false;
    }

    @Override
    public void clear() {
      multimap().clear();
    }
  }

  public static void assertMapEntryIsUnmodifiable(Entry<?, ?> entry) {
    try {
      // fine because the call is going to fail without modifying the entry
      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);
      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {

    public boolean remove(@Nullable Object o) {
      if (o instanceof Entry) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        if (unfiltered.containsKey(entry.getKey())
            // if this holds, then we know entry.getKey() is a K
            && keyPredicate.apply((K) entry.getKey())) {
          return unfiltered.remove(entry.getKey(), entry.getValue());
        }
      }
      return false;
    }
  }

    public boolean remove(@Nullable Object o) {
      if (o instanceof Entry) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        if (unfiltered.containsKey(entry.getKey())
            // if this holds, then we know entry.getKey() is a K
            && keyPredicate.apply((K) entry.getKey())) {
          return unfiltered.remove(entry.getKey(), entry.getValue());
        }
      }
      return false;
    }
  }

  }

  @Override
  public @Nullable Entry<E> firstEntry() {
    return forwardMultiset().lastEntry();
  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return forwardMultiset().firstEntry();
  }

  abstract Iterator<Entry<E>> entryIterator();

  @Nullable private transient Set<Entry<E>> entrySet;

  @Override
  public Set<Entry<E>> entrySet() {
    Set<Entry<E>> result = entrySet;

  public @Nullable Entry<E> pollFirstEntry() {
    Iterator<Entry<E>> entryIterator = entryIterator();
    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();
      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {

    private final OneSizeTestContainerGenerator<Map<K, V>, Entry<K, V>> mapGenerator;

    ReserializedMapGenerator(OneSizeTestContainerGenerator<Map<K, V>, Entry<K, V>> mapGenerator) {
      this.mapGenerator = mapGenerator;
    }

    @Override
    public SampleElements<Entry<K, V>> samples() {
      return mapGenerator.samples();
    }

    @Override
    public Entry<K, V>[] createArray(int length) {

    @Override
    protected final Map<String, String> create(Entry<String, String>[] entries) {
      HashMap<String, String> map = new HashMap<>();
      for (Entry<String, String> entry : entries) {
        map.put(entry.getKey(), entry.getValue());
      }
      return wrap(map);
    }

    abstract Map<String, String> wrap(HashMap<String, String> map);
  }

    Iterator<E> iterator = collection.iterator();
    Object element = iterator.next();
    // If it's an Entry, it may become invalid once it's removed from the Map. Copy it.
    if (element instanceof Entry) {
      Entry<?, ?> entry = (Entry<?, ?>) element;
      element = mapEntry(entry.getKey(), entry.getValue());
    }
    assertTrue(collection.contains(element)); // sanity check
    iterator.remove();

    private final Entry<K, V> delegate;

    static <K, V extends @Nullable Object> Set<Entry<K, V>> transformEntries(
        Set<Entry<K, V>> entries) {
      return new ForwardingSet<Map.Entry<K, V>>() {
        @Override
        protected Set<Entry<K, V>> delegate() {
          return entries;
        }

        @Override
        public Iterator<Entry<K, V>> iterator() {