}

  static <
          T extends @Nullable Object,
          K extends @Nullable Object,
          V extends @Nullable Object,
          M extends Multimap<K, V>>
      Collector<T, ?, M> toMultimap(
          Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction,
          Supplier<M> multimapSupplier) {
    checkNotNull(keyFunction);

   *
   *  * `Authorization`
   *  * `Cookie`
   *  * `Proxy-Authorization`
   *  * `Set-Cookie`
   */
  override fun toString(): String = commonToString()

  fun toMultimap(): Map<String, List<String>> {
    val result = TreeMap<String, MutableList<String>>(String.CASE_INSENSITIVE_ORDER)
    for (i in 0 until size) {
      val name = name(i).lowercase(Locale.US)

 *  **Interceptors lists are now deep-copied by `OkHttpClient.clone()`.**
    Previously clones shared interceptors, which made it difficult to customize
    the interceptors on a request-by-request basis.

 *  New: `Headers.toMultimap()`.
 *  New: `RequestBody.create(MediaType, ByteString)`.
 *  New: `ConnectionSpec.isCompatible(SSLSocket)`.
 *  New: `Dispatcher.getQueuedCallCount()` and

    val values: List<String> = headers.values("")
    val byteCount: Long = headers.byteCount()
    val builder: Headers.Builder = headers.newBuilder()
    val multimap: Map<String, List<String>> = headers.toMultimap()
  }

  @Test
  fun headersBuilder() {
    var builder: Headers.Builder = Headers.Builder()
    builder = builder.add("")
    builder = builder.add("", "")