* optimization and opened up a weird type-safety problem.
     */

    @Override
    public String toString() {
      return "Converter.identity()";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0L;
  }

    final ImmutableMultimap<?, ?> multimap;

    KeysSerializedForm(ImmutableMultimap<?, ?> multimap) {
      this.multimap = multimap;
    }

    Object readResolve() {
      return multimap.keys();
    }
  }

  /**
   * Returns an immutable collection of the values in this multimap. Its iterator traverses the

      int i = 0;
      for (Entry<E> entry : multiset.entrySet()) {
        elements[i] = entry.getElement();
        counts[i] = entry.getCount();
        i++;
      }
    }

    Object readResolve() {
      int n = elements.length;
      Builder<E> builder = new Builder<>(comparator);
      for (int i = 0; i < n; i++) {
        builder.addCopies(elements[i], counts[i]);
      }
      return builder.build();

    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override
    public String toString() {
      return "Floats.stringConverter()";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;
  }

  /**

      this.data = LockFreeBitArray.toPlainArray(bf.bits.data);
      this.numHashFunctions = bf.numHashFunctions;
      this.funnel = bf.funnel;
      this.strategy = bf.strategy;
    }

    Object readResolve() {
      return new BloomFilter<T>(new LockFreeBitArray(data), numHashFunctions, funnel, strategy);
    }

    private static final long serialVersionUID = 1;
  }

  /**

    protected String doBackward(Double value) {
      return value.toString();
    }

    @Override
    public String toString() {
      return "Doubles.stringConverter()";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;
  }

  /**

  private static final class SerializedForm implements Serializable {
    final Object[] elements;

    SerializedForm(Object[] elements) {
      this.elements = elements;
    }

    Object readResolve() {
      return copyOf(elements);
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  @Override
  @J2ktIncompatible
    Object writeReplace() {

    protected String doBackward(Long value) {
      return value.toString();
    }

    @Override
    public String toString() {
      return "Longs.stringConverter()";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;
  }

  /**

    SerializedForm(Comparator<? super E> comparator, Object[] elements) {
      this.comparator = comparator;
      this.elements = elements;
    }

    @SuppressWarnings("unchecked")
    Object readResolve() {
      return new Builder<E>(comparator).add((E[]) elements).build();
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  @J2ktIncompatible // serialization