return "index.json";
    }

    @Override
    public String format(final Map<String, Object> source, final Set<String> excludeFields) {
        final StringBuilder json = new StringBuilder();
        json.append("{\n");

        boolean first = true;
        for (final Map.Entry<String, Object> entry : source.entrySet()) {
            final String field = entry.getKey();

    }

    @Override
    public void acceptAllColumnMap(Entity entity, Map<String, ? extends Object> allColumnMap) {
    }

    @Override
    public Map<String, Object> extractPrimaryKeyMap(Entity entity) {
        return null;
    }

    @Override
    public Map<String, Object> extractAllColumnMap(Entity entity) {
        return null;

    }

    @Override
    public void acceptAllColumnMap(Entity entity, Map<String, ? extends Object> allColumnMap) {
    }

    @Override
    public Map<String, Object> extractPrimaryKeyMap(Entity entity) {
        return null;
    }

    @Override
    public Map<String, Object> extractAllColumnMap(Entity entity) {
        return null;

   */
  static boolean safeRemove(Collection<?> collection, @Nullable Object object) {
    checkNotNull(collection);
    try {
      return collection.remove(object);
    } catch (ClassCastException | NullPointerException e) {
      return false;
    }
  }

  static class FilteredCollection<E extends @Nullable Object> extends AbstractCollection<E> {
    final Collection<E> unfiltered;

    /**
     * @throws Exception
     */
    @Test
    public void testPerformance() throws Exception {
        int num = 100000;
        Map<String, Object> hmap = new HashMap<String, Object>();
        Map<String, Object> amap = new ArrayMap<String, Object>();

        long start = System.currentTimeMillis();
        for (int i = 0; i < num; i++) {
            hmap.put(String.valueOf(i), null);
        }

    }

    @Override
    public void acceptAllColumnMap(Entity entity, Map<String, ? extends Object> allColumnMap) {
    }

    @Override
    public Map<String, Object> extractPrimaryKeyMap(Entity entity) {
        return null;
    }

    @Override
    public Map<String, Object> extractAllColumnMap(Entity entity) {
        return null;

```
KEY:
storage_class  define object level redundancy

ARGS:
standard  (string)    set the parity count for default standard storage class e.g. "EC:4"
rrs       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
comment   (sentence)  optionally add a comment to this setting
```

or environment variables

```
KEY:
storage_class  define object level redundancy

ARGS:

     * @return An empty map.
     */
    public Map<String, Object> toEmptyMap() {
        return emptySource;
    }

    /**
     * Creates an empty map with default values for suggest item fields.
     * @return An empty map.
     */
    protected Map<String, Object> createEmptyMap() {
        final Map<String, Object> map = new HashMap<>();
        map.put(FieldNames.TEXT, StringUtil.EMPTY);

      @Override
      @J2ktIncompatible
      @GwtIncompatible
            Object writeReplace() {
        return super.writeReplace();
      }
    };
  }

  // redeclare to help optimizers with b/310253115
  @SuppressWarnings("RedundantOverride")
  @Override
  @J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

/**
 * Implementation of {@link Multimaps#filterKeys(ListMultimap, Predicate)}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class FilteredKeyListMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends FilteredKeyMultimap<K, V> implements ListMultimap<K, V> {
  FilteredKeyListMultimap(ListMultimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    super(unfiltered, keyPredicate);
  }