release has many critical bug fixes and is safe to run in production. We're eager to stabilize our
new APIs so we can get out of alpha.

 *  New: Support Java 21's virtual threads (‘OpenJDK Project Loom’). We changed OkHttp's internals
    to use `Lock` and `Condition` instead of `synchronized` for best resource utilization.

   * is what most users want and expect it to do.
   *
   * <p>This behavior can't be broadly guaranteed, but has been tested with OpenJDK 1.7 and 1.8.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty hash set with enough capacity to hold {@code expectedSize} elements
   *     without resizing

 *  New: Upgrade to Conscrypt 2.0.0. OkHttp works with other versions of Conscrypt but this is the
    version we're testing against.

    ```kotlin
    implementation("org.conscrypt:conscrypt-openjdk-uber:2.0.0")
    ```

 *  New: Update the embedded public suffixes list.


## Version 3.13.1

_2019-02-05_

 * Added support for compressed data frames.
 * Process push promise callbacks in order.
 * Update to http/2 draft 12.
 * Update to HPACK draft 07.
 * Add ALPN support. Maven will use ALPN on OpenJDK 8.
 * Update NPN dependency to target `jdk7u60-b13` and `Oracle jdk7u55-b13`.
 * Ensure SPDY variants support zero-length DELETE and POST.
 * Prevent leaking a cache item's InputStreams when metadata read fails.

   * hold {@code expectedSize} elements without growth. This behavior cannot be broadly guaranteed,
   * but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed that the method
   * isn't inadvertently <i>oversizing</i> the returned map.
   *
   * @param expectedSize the number of entries you expect to add to the returned map

   * hold {@code expectedSize} elements without growth. This behavior cannot be broadly guaranteed,
   * but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed that the method
   * isn't inadvertently <i>oversizing</i> the returned map.
   *
   * @param expectedSize the number of entries you expect to add to the returned map

    executeSynchronously("/")
      .assertFailureMatches("(?s)Hostname localhost not verified.*")
  }

  /**
   * Anonymous cipher suites were disabled in OpenJDK because they're rarely used and permit
   * man-in-the-middle attacks. https://bugs.openjdk.java.net/browse/JDK-8212823
   */
  @Test
  fun anonCipherSuiteUnsupported() {
    platform.assumeNotConscrypt()
    platform.assumeNotBouncyCastle()

    val request = Request.Builder().url(server.url("/")).build()
    val response1 = client.newCall(request).execute()
    val source = response1.body.source()
    assertThat(source.readUtf8()).isEqualTo("ABC")

    // OpenJDK 6 fails on this line, complaining that the connection isn't open yet
    val cipherSuite = response1.handshake!!.cipherSuite
    val localCerts = response1.handshake!!.localCertificates

    assertContent("def", getResponse(newRequest("/")))
    val tlsVersions: Set<TlsVersion?> =
      EnumSet.of(
        TlsVersion.TLS_1_0,
        TlsVersion.TLS_1_2,
        TlsVersion.TLS_1_3,
      ) // v1.2 on OpenJDK 8.
    val request1 = server.takeRequest()
    assertThat(tlsVersions).contains(request1.handshake?.tlsVersion)
    val request2 = server.takeRequest()
    assertThat(tlsVersions).contains(request2.handshake?.tlsVersion)