throw ProtocolException(
        "Expected HTTP 101 response but was '${response.code} ${response.message}'",
      )
    }

    val headerConnection = response.header("Connection")
    if (!"Upgrade".equals(headerConnection, ignoreCase = true)) {
      throw ProtocolException(
        "Expected 'Connection' header value 'Upgrade' but was '$headerConnection'",
      )
    }

  }

  /** Returns true if there's another proxy to try. */
  private fun hasNextProxy(): Boolean = nextProxyIndex < proxies.size

  /** Returns the next proxy to try. May be PROXY.NO_PROXY but never null. */
  @Throws(IOException::class)
  private fun nextProxy(): Proxy {
    if (!hasNextProxy()) {
      throw SocketException(
        "No route to ${address.url.host}; exhausted proxy configurations: $proxies",

URLs are abstract:

      if (logger.isLoggable(FINE)) logger.fine(format("<< CONNECTION ${connectionPreface.hex()}"))
      if (CONNECTION_PREFACE != connectionPreface) {
        throw IOException("Expected a connection header but was ${connectionPreface.utf8()}")
      }
    }
  }

  @Throws(IOException::class)
  fun nextFrame(
    requireSettings: Boolean,
    handler: Handler,
  ): Boolean {
    try {

     * semantics are different. In particular, each of the body parts is an "alternative" version of
     * the same information.
     */
    @JvmField
    val ALTERNATIVE = "multipart/alternative".toMediaType()

    /**
     * This type is syntactically identical to "multipart/mixed", but the semantics are different.

            .networkResponse(networkResponse.stripBody())
            .build()

        networkResponse.body.close()

        // Update the cache after combining headers but before stripping the
        // Content-Encoding header (as performed by initContentStream()).
        cache!!.trackConditionalCacheHit()
        cache.update(cacheResponse, response)
        return response.also {

      .assertNoMoreLogs()
  }

  @Test
  fun bodyResponseUnknownEncoded() {
    setLevel(Level.BODY)
    server.enqueue(
      MockResponse.Builder() // It's invalid to return this if not requested, but the server might anyway
        .setHeader("Content-Encoding", "br")
        .setHeader("Content-Type", PLAIN)
        .body(Buffer().write("iwmASGVsbG8sIEhlbGxvLCBIZWxsbwoD".decodeBase64()!!))
        .build(),
    )

  sink(file).use {
    try {
      delete(file)
      return true
    } catch (_: IOException) {
    }
  }
  delete(file)
  return false
}

/** Delete file we expect but don't require to exist. */
internal fun FileSystem.deleteIfExists(path: Path) {
  try {
    delete(path)
  } catch (fnfe: FileNotFoundException) {
    return
  }
}

#
#   Gradle start up script for POSIX generated by Gradle.
#
#   Important for running:
#
#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
#       noncompliant, but you have some other compliant shell such as ksh or
#       bash, then to run this script, type that shell name before the whole
#       command line, like:
#
#           ksh Gradle
#

    managed both idle and active connections for HTTP/2, but only idle
    connections for HTTP/1.x. With this update the connection pool manages both
    idle and active connections for everything. OkHttp now detects and warns on
    connections that were allocated but never released, and will enforce HTTP/2
    stream limits. This update also fixes `Call.cancel()` to not do I/O on the