}
    }

    /**
     * Returns true if none of the Vary headers have changed between [cachedRequest] and
     * [newRequest].
     */
    fun varyMatches(
      cachedResponse: Response,
      cachedRequest: Headers,
      newRequest: Request,
    ): Boolean {
      return cachedResponse.headers.varyFields().none {
        cachedRequest.values(it) != newRequest.headers(it)
      }
    }

Some requests will have a cached response. When this cached response isn’t fresh, OkHttp can do a _conditional GET_ to download an updated response if it’s newer than what’s cached. This requires headers like `If-Modified-Since` and `If-None-Match` to be added.

## Rewriting Responses

    fromSource: BufferedSource,
    fromSink: BufferedSink,
  ) {
    val version = fromSource.readByte() and 0xff
    val methodCount = fromSource.readByte() and 0xff
    var selectedMethod = METHOD_NONE
    if (version != VERSION_5) {
      throw ProtocolException("unsupported version: $version")
    }
    for (i in 0 until methodCount) {
      val candidateMethod: Int = fromSource.readByte() and 0xff

        override fun callFailed(
          call: Call,
          ioe: IOException,
        ) = TODO()

        override fun canceled(call: Call) = TODO()
      }
    val none: EventListener = EventListener.NONE
  }

  @Test
  fun eventListenerBuilder() {
    var builder: EventListener.Factory = EventListener.Factory { TODO() }
  }

  @Test
  fun formBody() {

   * the same order. Note that two headers instances may be *semantically* equal but not equal
   * according to this method. In particular, none of the following sets of headers are equal
   * according to this method:
   *
   * 1. Original
   * ```
   * Content-Type: text/html
   * Content-Length: 50
   * ```
   *
   * 2. Different order

```
INFO: Sending request http://www.publicobject.com/helloworld.txt on Connection{www.publicobject.com:80, proxy=DIRECT hostAddress=54.187.32.157 cipherSuite=none protocol=http/1.1}
User-Agent: OkHttp Example
Host: www.publicobject.com
Connection: Keep-Alive
Accept-Encoding: gzip

INFO: Received response for http://www.publicobject.com/helloworld.txt in 115.6ms

    val networkRequest = strategy.networkRequest
    val cacheResponse = strategy.cacheResponse

    cache?.trackResponse(strategy)
    val listener = (call as? RealCall)?.eventListener ?: EventListener.NONE

    if (cacheCandidate != null && cacheResponse == null) {
      // The cache candidate wasn't applicable. Close it.
      cacheCandidate.body.closeQuietly()
    }

          sink: Buffer,
          byteCount: Long,
        ): Long {
          check(!closed)
          return data.read(sink, byteCount)
        }

        override fun timeout(): Timeout {
          return Timeout.NONE
        }
      }
    return source.buffer().asResponseBody(null, -1)
  }

  private fun newResponse(
    responseBody: ResponseBody,
    code: Int = 200,
    fn: Response.Builder.() -> Unit = {},

      .assertLogMatch(Regex("""connectEnd: http/1.1"""))
      .assertLogMatch(
        Regex(
          """connectionAcquired: Connection\{${url.host}:\d+, proxy=DIRECT hostAddress=${url.host}/.+ cipherSuite=none protocol=http/1\.1\}""",
        ),
      )
      .assertLogMatch(Regex("""requestHeadersStart"""))
      .assertLogMatch(Regex("""requestHeadersEnd"""))
      .assertLogMatch(Regex("""responseHeadersStart"""))

  ): RouteSelector {
    return RouteSelector(
      address = address,
      routeDatabase = routeDatabase,
      fastFallback = fastFallback,
      connectionUser = CallConnectionUser(call, ConnectionListener.NONE, newChain(call)),
    )
  }

  private fun newChain(call: RealCall): RealInterceptorChain {
    return RealInterceptorChain(
      call = call,
      interceptors = listOf(),
      index = 0,