instead of notifying the thread's uncaught exception handler. We've added a
    new API, `Call.isCanceled()` to check if a call has been canceled.

 *  New: Update `MultipartBuilder` to support content length.
 *  New: Make it possible to mock `OkHttpClient` and `Call`.
 *  New: Update to h2-14 and hpack-9.
 *  New: OkHttp includes a user-agent by default, like `okhttp/2.1.0-RC1`.

and the matching call to <code>l.RUnlock</code> is synchronized before the return from call <i>n</i>+1 to <code>l.Lock</code>.
</p>

<p class="rule">
A successful call to <code>l.TryLock</code> (or <code>l.TryRLock</code>)
is equivalent to a call to <code>l.Lock</code> (or <code>l.RLock</code>).
An unsuccessful call has no synchronizing effect at all.
As far as the memory model is concerned,

 * Implementations of this interface should respond to [Call.cancel] by immediately throwing an
 * [IOException].
 *
 * Most callers won't need this interface, and should use [Response.trailers] instead.
 *
 * This interface is for test and production code that creates [Response] instances without making
 * an HTTP call to a remote server.
 */
interface TrailersSource {
  @Throws(IOException::class)

  @Throws(InterruptedException::class)
  override fun dispatch(request: RecordedRequest): MockResponse = throw UnsupportedOperationException("unexpected call")

  override fun peek(): MockResponse = throw UnsupportedOperationException("unexpected call")

  fun enqueueResponse(response: MockResponse) {
    delegate.enqueue(response.wrap())
  }

  override fun shutdown() {
    delegate.close()
  }

const maxInt = int(^uint(0) >> 1)

// Bytes returns a slice of length b.Len() holding the unread portion of the buffer.
// The slice is valid for use only until the next buffer modification (that is,
// only until the next call to a method like [Buffer.Read], [Buffer.Write], [Buffer.Reset], or [Buffer.Truncate]).
// The slice aliases the buffer content at least until the next buffer modification,

   * receiving. With duplex the request and response may be interleaved! That is, request body bytes
   * may be sent after response headers or body bytes have been received.
   *
   * Though any call may be initiated as a duplex call, only web servers that are specially
   * designed for this nonstandard interaction will use it. As of 2019-01, the only widely-used
   * implementation of this pattern is [gRPC][grpc].
   *

   * skipped element by immediately calling {@code remove()} on the returned fluent iterable's
   * iterator, as the {@code Iterator} contract states that a call to {@code * remove()} before a
   * call to {@code next()} will throw an {@link IllegalStateException}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Stream#skip} (same).
   */
  public final FluentIterable<E> skip(int numberToSkip) {

   * skipped element by immediately calling {@code remove()} on the returned fluent iterable's
   * iterator, as the {@code Iterator} contract states that a call to {@code * remove()} before a
   * call to {@code next()} will throw an {@link IllegalStateException}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Stream#skip} (same).
   */
  public final FluentIterable<E> skip(int numberToSkip) {

    val call = calls[0]
    assertThat(call).contains("host=" + url.host)
    assertThat(call).contains("port=" + url.port)
    assertThat(call).contains("site=" + url.host)
    assertThat(call).contains("url=$url")
    assertThat(call).contains("type=" + java.net.Authenticator.RequestorType.SERVER)
    assertThat(call).contains("prompt=Bar")
    assertThat(call).contains("protocol=http")

    if (subjectGenerator == null) {
      throw new IllegalStateException("Call using() before createTestSuite().");
    }
    if (name == null) {
      throw new IllegalStateException("Call named() before createTestSuite().");
    }
    if (features == null) {
      throw new IllegalStateException("Call withFeatures() before createTestSuite().");
    }
  }