internal const val B0_FLAG_FIN = 128

  /** Byte 0 reserved flag 1. Must be 0 unless negotiated otherwise. */
  internal const val B0_FLAG_RSV1 = 64

  /** Byte 0 reserved flag 2. Must be 0 unless negotiated otherwise. */
  internal const val B0_FLAG_RSV2 = 32

  /** Byte 0 reserved flag 3. Must be 0 unless negotiated otherwise. */
  internal const val B0_FLAG_RSV3 = 16

  /** Byte 0 mask for the frame opcode. */

   * HTTPS.
   */
  fun handshake(): Handshake?

  /**
   * Returns the protocol negotiated by this connection, or [Protocol.HTTP_1_1] if no protocol
   * has been negotiated. This method returns [Protocol.HTTP_1_1] even if the remote peer is using
   * [Protocol.HTTP_1_0].
   */
  fun protocol(): Protocol

            ) {
              val sslSocket = connection.socket() as SSLSocket
              println("Requested " + sslSocket.sslParameters.applicationProtocols.joinToString())
              println("Negotiated " + sslSocket.applicationProtocol)
            }
          },
        ).build()

    val request =
      Request
        .Builder()
        .url("https://www.google.com")
        .build()

  ) {
  }

  /** Called after the TLS handshake to release resources allocated by [configureTlsExtensions]. */
  open fun afterHandshake(sslSocket: SSLSocket) {
  }

  /** Returns the negotiated protocol, or null if no protocol was negotiated. */
  open fun getSelectedProtocol(sslSocket: SSLSocket): String? = null

  /** For MockWebServer. This returns the inbound SNI names. */

          message == "No session to resume." -> Type.Handshake
          message.startsWith("Consuming ") -> Type.Handshake
          message.startsWith("Produced ") -> Type.Handshake
          message.startsWith("Negotiated ") -> Type.Handshake
          message.startsWith("Found resumable session") -> Type.Handshake
          message.startsWith("Resuming session") -> Type.Handshake

   OkHttp.
 * Expose the transport ("http/1.1", "spdy/3", etc.) via magic request headers.
   Use `X-Android-Transports` to write the preferred transports and
   `X-Android-Selected-Transport` to read the negotiated transport.


## Version 1.0.2

_2013-05-11_

 * Fix: Remove use of Java 6-only APIs.
 * Fix: Properly handle exceptions from `NetworkInterface` when querying MTU.

 * **reactive** authentication after receiving a challenge from either an origin web server or proxy
 * server.
 *
 * ## Preemptive Authentication
 *
 * To make HTTPS calls using an HTTP proxy server OkHttp must first negotiate a connection with
 * the proxy. This proxy connection is called a "TLS Tunnel" and is specified by
 * [RFC 2817][1]. The HTTP CONNECT request that creates this tunnel connection is special: it

There may be many routes for a single address. For example, a webserver that is hosted in multiple datacenters may yield multiple IP addresses in its DNS response.