*
     * @param pairs the list of AV pairs to modify
     * @param rep the replacement AV pair
     */
    public static void replace(final List<AvPair> pairs, final AvPair rep) {
        remove(pairs, rep.getType());
        pairs.add(rep);
    }

    /**
     * Encodes a list of AV pairs into byte array format
     *
     * @param pairs the list of AV pairs to encode
     * @return encoded avpairs

        List<AvPair> pairs = AvPairs.decode(fullData);

        assertNotNull(pairs, "Decoded pairs should not be null");
        assertEquals(1, pairs.size(), "Should have decoded one pair");

        AvPair pair = pairs.get(0);
        assertEquals(AvPair.MsvAvFlags, pair.getType(), "Pair type should be MsvAvFlags");
        assertTrue(pair instanceof AvFlags, "Should be decoded as AvFlags");

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

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

    assertThat(headers["e"]).isNull()
  }

  @Test fun iteratorOperator() {
    val headers = headersOf("a", "b", "c", "d")

    val pairs = mutableListOf<Pair<String, String>>()
    for ((name, value) in headers) {
      pairs += name to value
    }

    assertThat(pairs).containsExactly("a" to "b", "c" to "d")
  }

  @Test fun builderGetOperator() {
    val builder = Headers.Builder()
    builder.add("a", "b")

  // Modification Operations

  /**
   * Stores a key-value pair in this multimap.
   *
   * <p>Some multimap implementations allow duplicate key-value pairs, in which case {@code put}
   * always adds a new key-value pair and increases the multimap size by 1. Other implementations
   * prohibit duplicates, and storing a key-value pair that's already in the multimap has no effect.
   *

  // Modification Operations

  /**
   * Stores a key-value pair in this multimap.
   *
   * <p>Some multimap implementations allow duplicate key-value pairs, in which case {@code put}
   * always adds a new key-value pair and increases the multimap size by 1. Other implementations
   * prohibit duplicates, and storing a key-value pair that's already in the multimap has no effect.
   *

     * 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.
     *

    Escapers.Builder builder = Escapers.builder();
    // The char values \uFFFE and \uFFFF are explicitly not allowed in XML
    // (Unicode code points above \uFFFF are represented via surrogate pairs
    // which means they are treated as pairs of safe characters).
    builder.setSafeRange(Character.MIN_VALUE, '\uFFFD');
    // Unsafe characters are replaced with the Unicode replacement character.
    builder.setUnsafeReplacement("\uFFFD");