assertEquals("abc", Strings.commonPrefix(new StringBuffer("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(
        "abc\uD8AB\uDCAB", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
    // Differing valid surrogate pairs.
    assertEquals("abc", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCACxyz"));
    // One invalid pair.

    assertEquals("abc", Strings.commonPrefix(new StringBuffer("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(
        "abc\uD8AB\uDCAB", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
    // Differing valid surrogate pairs.
    assertEquals("abc", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCACxyz"));
    // One invalid pair.

 * map from keys to <i>nonempty</i> collections of values:
 *
 * <ul>
 *   <li>a → 1, 2
 *   <li>b → 3
 * </ul>
 *
 * ... or as a single "flattened" collection of key-value pairs:
 *
 * <ul>
 *   <li>a → 1
 *   <li>a → 2
 *   <li>b → 3
 * </ul>
 *
 * <p><b>Important:</b> although the first interpretation resembles how most multimaps are

     * soon be deprecated.
     *
     * @throws IllegalArgumentException if duplicate key pairs were added
     */
    public ImmutableTable<R, C, V> build() {
      return buildOrThrow();
    }

    /**
     * Returns a newly-created immutable table, or throws an exception if duplicate key pairs were
     * added.
     *

     * soon be deprecated.
     *
     * @throws IllegalArgumentException if duplicate key pairs were added
     */
    public ImmutableTable<R, C, V> build() {
      return buildOrThrow();
    }

    /**
     * Returns a newly-created immutable table, or throws an exception if duplicate key pairs were
     * added.
     *

	return mg
}

// AddExtraLabels - adds extra (constant) label KV pairs to the metrics group.
// This is a helper to initialize the `ExtraLabels` field. The argument is a
// list of ordered label name and value pairs.
func (mg *MetricsGroup) AddExtraLabels(labels ...string) {
	if len(labels)%2 != 0 {
		panic("Labels must be an ordered list of name value pairs")
	}
	if mg.ExtraLabels == nil {

      Comparator<Entry<K, V>> entryComparator(@Nullable Comparator<? super K> keyComparator) {
    return new EntryComparator<K, V>(keyComparator);
  }

  /**
   * Asserts that all pairs of {@code T} values within {@code valuesInExpectedOrder} are ordered
   * consistently between their order within {@code valuesInExpectedOrder} and the order implied by
   * the given {@code comparator}.
   *

      Comparator<Entry<K, V>> entryComparator(@Nullable Comparator<? super K> keyComparator) {
    return new EntryComparator<K, V>(keyComparator);
  }

  /**
   * Asserts that all pairs of {@code T} values within {@code valuesInExpectedOrder} are ordered
   * consistently between their order within {@code valuesInExpectedOrder} and the order implied by
   * the given {@code comparator}.
   *

 * difference. A CharEscaper can only process Java <a
 * href="http://en.wikipedia.org/wiki/UTF-16">UTF16</a> characters in isolation and may not cope
 * when it encounters surrogate pairs. This class facilitates the correct escaping of all Unicode
 * characters.
 *
 * <p>As there are important reasons, including potential security issues, to handle Unicode

    return new String(array);
  }

  /**
   * Returns the longest string {@code prefix} such that {@code a.toString().startsWith(prefix) &&
   * b.toString().startsWith(prefix)}, taking care not to split surrogate pairs. If {@code a} and
   * {@code b} have no common prefix, returns the empty string.
   *
   * @since 11.0
   */
  public static String commonPrefix(CharSequence a, CharSequence b) {
    checkNotNull(a);