static <K, V> ImmutableMapEntry<K, V>[] createEntryArray(int size) {
    return (ImmutableMapEntry<K, V>[]) new ImmutableMapEntry<?, ?>[size];
  }

  ImmutableMapEntry(K key, V value) {
    super(key, value);
    checkEntryNotNull(key, value);
  }

  ImmutableMapEntry(ImmutableMapEntry<K, V> contents) {
    super(contents.getKey(), contents.getValue());

        if (duplicates.containsKey(key)) {
          V value = duplicates.get(key);
          if (value == null) {
            continue; // delete this duplicate
          }
          entry = new ImmutableMapEntry<>(key, value);
          duplicates.put(key, null);
        }
        newEntryArray[outI++] = entry;
      }
      entryArray = newEntryArray;
    }

   *
   * <p>A call to {@link Entry#setValue} on the returned entry will always throw {@link
   * UnsupportedOperationException}.
   */
  static <K, V> Entry<K, V> entryOf(K key, V value) {
    return new ImmutableMapEntry<>(key, value);
  }

  /**
   * Returns a new builder. The generated builder is equivalent to the builder created by the {@link
   * Builder} constructor.
   */