}

  /**
   * Either writes this request to [sink] or measures its content length. We have one method
   * do double-duty to make sure the counting and content are consistent, particularly when it comes
   * to awkward operations like measuring the encoded length of header strings, or the
   * length-in-digits of an encoded integer.
   */
  private fun writeOrCountBytes(
    sink: BufferedSink?,
    countBytes: Boolean,
  ): Long {

     * values must be between 1 and [Integer.MAX_VALUE] when converted to milliseconds.
     *
     * The read timeout is applied to both the TCP socket and for individual read IO operations
     * including on [Source] of the [Response]. The default value is 10 seconds.
     *
     * @see Socket.setSoTimeout
     * @see Source.timeout
     */
    fun readTimeout(
      timeout: Long,

  // performed while holding this lock!
  //
  // Socket writes are guarded by frameWriter.
  //
  // Socket reads are unguarded but are only made by the reader thread.
  //
  // Certain operations (like SYN_STREAM) need to synchronize on both the frameWriter (to do
  // blocking I/O) and this (to create streams). Such operations must synchronize on 'this' last.

  val referer: String? by option("-e", "--referer", help = "Referer URL")

  val verbose: Boolean by option("-v", "--verbose", help = "Makes $NAME verbose during the operation").flag()

  val sslDebug: Boolean by option(help = "Output SSL Debug").flag()

  val url: String? by argument(name = "url", help = "Remote resource URL")

  var client: Call.Factory? = null

   */
  @Throws(UnknownHostException::class)
  fun lookup(hostname: String): List<InetAddress>

  companion object {
    /**
     * A DNS that uses [InetAddress.getAllByName] to ask the underlying operating system to
     * lookup IP addresses. Most custom [Dns] implementations should delegate to this instance.
     */
    @JvmField
    val SYSTEM: Dns = DnsSystem()

    private class DnsSystem : Dns {

        return new MetricsEventListener(call);
      } else {
        return EventListener.NONE;
      }
    }
  };

  ...
}
```

### Events with Failures

  /**
   * Either writes this request to [sink] or measures its content length. We have one method do
   * double-duty to make sure the counting and content are consistent, particularly when it comes
   * to awkward operations like measuring the encoded length of header strings, or the
   * length-in-digits of an encoded integer.
   */
  @Throws(IOException::class)
  private fun writeOrCountBytes(
    sink: BufferedSink?,

compression features. We strive to offer great performance in our default configuration and so we're
making compression the default for everyone starting with this release candidate.

Please be considerate of your servers and their operators as you roll out this release. Compression
saves bandwidth but it costs CPU and memory! If you run into a problem you may need to adjust or
disable the `permessage-deflate` compression settings on your server.

     *
     * This method is invoked after [call] is created. See [OkHttpClient.newCall].
     *
     * **It is an error for implementations to issue any mutating operations on the [call] instance
     * from this method.**
     */
    fun create(call: Call): EventListener
  }

  companion object {
    @JvmField
    val NONE: EventListener =

   *
   *   o READ lines track accesses for LRU.
   *
   *   o REMOVE lines track entries that have been deleted.
   *
   * The journal file is appended to as cache operations occur. The journal may occasionally be
   * compacted by dropping redundant lines. A temporary file named "journal.tmp" will be used during
   * compaction; that file should be deleted if it exists when the cache is opened.