*  New: Publish a [bill of materials (BOM)][bom] for OkHttp. Depend on this from Gradle or Maven to
    keep all of your OkHttp artifacts on the same version, even if they're declared via transitive
    dependencies. You can even omit versions when declaring other OkHttp dependencies.

    ```kotlin
    dependencies {
       api(platform("com.squareup.okhttp3:okhttp-bom:4.4.0"))
       api("com.squareup.okhttp3:okhttp")              // No version!

 * certificate is signed by the certificate that follows, and the last certificate is a trusted CA
 * certificate.
 *
 * Use of the chain cleaner is necessary to omit unexpected certificates that aren't relevant to
 * the TLS handshake and to extract the trusted CA certificate for the benefit of certificate
 * pinning.
 */
abstract class CertificateChainCleaner {

    Adapters.usingTypeHint { typeHint ->
      when (typeHint) {
        // This type is pretty strange. The spec says that for certain algorithms we must encode null
        // when it is present, and for others we must omit it!
        // https://tools.ietf.org/html/rfc4055#section-2.1
        ObjectIdentifiers.SHA256_WITH_RSA_ENCRYPTION -> Adapters.NULL
        ObjectIdentifiers.RSA_ENCRYPTION -> Adapters.NULL

      if (currentRunLength > longestRunLength && currentRunLength >= 4) {
        longestRunOffset = currentRunOffset
        longestRunLength = currentRunLength
      }
      i += 2
    }
  }

  // Emit each 2-byte group in hex, separated by ':'. The longest run of zeroes is "::".
  val result = Buffer()
  var i = 0
  while (i < address.size) {
    if (i == longestRunOffset) {
      result.writeByte(':'.code)

    assertFailsWith<IllegalStateException> {
      sinkReference.get().flush()
    }
    assertFailsWith<IllegalStateException> {
      sinkReference.get().write("ghi".toByteArray())
      sinkReference.get().emit()
    }
  }

  @Test
  fun getHeadersThrows() {
    server.enqueue(MockResponse(socketPolicy = SocketPolicy.DisconnectAtStart))
    assertFailsWith<IOException> {
      getResponse(newRequest("/"))

 *  Fix: Don't log the protocol (HTTP/1.1, h2) in HttpLoggingInterceptor if the
    protocol isn't negotiated yet! Previously we'd log HTTP/1.1 by default, and
    this was confusing.
 *  Fix: Omit the message from MockWebServer's HTTP/2 `:status` header.
 *  Fix: Handle 'Expect: 100 Continue' properly in MockWebServer.


## Version 3.8.1

_2017-06-18_

 *  New: `Request.Builder.cacheUrlOverride()` customizes the cache key used for a request. This can
    be used to make canonical URLs for the cache that omit insignificant query parameters or other
    irrelevant data.

    This feature may be used with `POST` requests to cache their responses. In such cases the

   * they will be absent (unless they were already returned).
   *
   * If there are I/O problems during iteration, this iterator fails silently. For example, if the
   * hosting filesystem becomes unreachable, the iterator will omit elements rather than throwing
   * exceptions.
   *
   * **The caller must [close][Snapshot.close]** each snapshot returned by [Iterator.next]. Failing
   * to do so leaks open files!
   */
  @Synchronized

    server.webSocket!!.finishReader()
    server.listener.assertClosed(1000, "Bye!")
  }

  @Test
  fun emptyCloseInitiatesShutdown() {
    server.sink.write("8800".decodeHex()).emit() // Close without code.
    client.processNextFrame()
    client.listener.assertClosing(1005, "")
    client.webSocket!!.finishReader()
    assertThat(client.webSocket!!.close(1000, "Bye!")).isTrue()

      }

      override fun writeTo(sink: BufferedSink) {
        val uppercase = uppercase(sink)
        val bufferedSink = uppercase.buffer()
        original!!.writeTo(bufferedSink)
        bufferedSink.emit()
      }
    }
  }

  private fun uppercase(original: BufferedSink): Sink {
    return object : ForwardingSink(original) {
      override fun write(
        source: Buffer,
        byteCount: Long,