*/
  static <K, V> Entry<K, V> entryOf(K key, V value) {
    checkEntryNotNull(key, value);
    return new AbstractMap.SimpleImmutableEntry<>(key, value);
  }

  /**
   * Returns a new builder. The generated builder is equivalent to the builder created by the {@link
   * Builder} constructor.
   */
  public static <K, V> Builder<K, V> builder() {
    return new Builder<>();
  }

  /**