*    negotiate HTTP/2.
 *
 * Unfortunately, older HTTPS servers refuse to connect when such options are presented. Rather than
 * avoiding these options entirely, this class allows a connection to be attempted with modern
 * options and then retried without them should the attempt fail.
 *
 * ## Connection Reuse
 *

 * implementing new escapers. It is strongly recommended that when implementing a new escaper you
 * extend one of these classes. If you find that you are unable to achieve the desired behavior
 * using either of these classes, please contact the Java libraries team for advice.
 *
 * <p>Popular escapers are defined as constants in classes like {@link

1. Script the mocks.
2. Run application code.
3. Verify that the expected requests were made.

Here's a complete example:

### Java
```java
public void test() throws Exception {
  // Create a MockWebServer. These are lean enough that you can create a new
  // instance for every unit test.
  MockWebServer server = new MockWebServer();

  // Schedule some responses.
  server.enqueue(new MockResponse.Builder()

        ? SortedSetTestSuiteBuilder.using((TestSortedSetGenerator<K>) keySetGenerator)
        : SetTestSuiteBuilder.using(keySetGenerator);
  }

  /**
   * To avoid infinite recursion, test suites with these marker features won't have derived suites
   * created for them.
   */
  enum NoRecurse implements Feature<@Nullable Void> {
    SUBMAP,
    DESCENDING;

    @Override

   * trouble than just using Object.class.)
   *
   * Then we declare the getters for these fields as @GwtIncompatible so that no one can try to use
   * them under J2CL—or, as an unfortunate side effect, under GWT. We do still give the fields
   * themselves their proper values under GWT, since GWT's EnumMap does need the Class instance.
   *
   * Note that sometimes these fields *do* have correct values under J2CL: They will if the caller

  private static final long K1 = 0x0f0e0d0c0b0a0908L;
  private static final HashFunction SIP_WITH_KEY = Hashing.sipHash24(K0, K1);
  private static final HashFunction SIP_WITHOUT_KEY = Hashing.sipHash24();

  // These constants were originally ported from https://www.131002.net/siphash/siphash24.c. See:
  // https://github.com/nahi/siphash-java-inline/blob/master/src/test/java/org/jruby/util/SipHashInlineTest.java

 *
 * <p>{@code ByteSink} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a stream:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned stream is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

 *
 * <p>{@code ByteSink} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a stream:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned stream is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

 * cause DNS services to be accessed. For this reason, you should prefer these methods as much as
 * possible over their JDK equivalents whenever you are expecting to handle only IP address string
 * literals -- there is no blocking DNS penalty for a malformed string.
 *
 * <p>When dealing with {@link Inet4Address} and {@link Inet6Address} objects as byte arrays (vis.

    it keeps your `HeldCertificate` and its chain. On the client it keeps the root certificates
    that are trusted to sign a server's certificate chain. `HandshakeCertificates` also works with
    mutual TLS where these roles are reversed.

    These classes make it possible to enable HTTPS in MockWebServer in [just a few lines of
    code][https_server_sample].

 *  **OkHttp now supports prior knowledge cleartext HTTP/2.** Enable this by setting