*  Fix: Don't crash when the URL hostname contains an underscore on Android.
 *  Fix: Change HTTP/2 to use a daemon thread for its socket reader. If you've ever seen a command
    line application hang after all of the work is done, it may be due to a non-daemon thread like
    this one.
 *  New: Include suppressed exceptions when all routes to a target service fail.


## Version 4.4.1

    fun writeTo(editor: DiskLruCache.Editor) {
      editor.newSink(ENTRY_METADATA).buffer().use { sink ->
        sink.writeUtf8(url.toString()).writeByte('\n'.code)
        sink.writeUtf8(requestMethod).writeByte('\n'.code)
        sink.writeDecimalLong(varyHeaders.size.toLong()).writeByte('\n'.code)
        for (i in 0 until varyHeaders.size) {
          sink.writeUtf8(varyHeaders.name(i))
            .writeUtf8(": ")

      val source = this.source!!
      val sink = this.sink!!
      val tunnelCodec =
        Http1ExchangeCodec(
          // No client for CONNECT tunnels:
          client = null,
          carrier = this,
          source = source,
          sink = sink,
        )
      source.timeout().timeout(readTimeoutMillis.toLong(), TimeUnit.MILLISECONDS)

      object : RequestBody() {
        override fun contentType(): MediaType? {
          return null
        }

        override fun writeTo(sink: BufferedSink) {
          sink.writeUtf8("Hello request!")
          sink.close()
        }

        override fun isDuplex(): Boolean {
          return true
        }
      }
    val request =
      request()

      writeHeaders(sink, response.trailers)
    }
  }

  @Throws(IOException::class)
  private fun writeHeaders(
    sink: BufferedSink,
    headers: Headers,
  ) {
    for ((name, value) in headers) {
      sink.writeUtf8(name)
      sink.writeUtf8(": ")
      sink.writeUtf8(value)
      sink.writeUtf8("\r\n")
    }
    sink.writeUtf8("\r\n")
    sink.flush()
  }

  /**
   * Returns a sink that can be used to write data to the peer.
   *
   * @throws IllegalStateException if this stream was initiated by the peer and a [writeHeaders] has
   *     not yet been sent.
   */
  fun getSink(): Sink {
    this.withLock {
      check(hasResponseHeaders || isLocallyInitiated) {
        "reply before requesting the sink"
      }
    }
    return sink
  }