var pos = 0
    val limit = string.length
    val result = Buffer()

    while (pos < limit) {
      var dot = string.indexOf('.', startIndex = pos)
      if (dot == -1) dot = limit

      if (!encodeLabel(string, pos, dot, result)) {
        // If we couldn't encode the label, give up.
        return null
      }

      if (dot < limit) {
        result.writeByte('.'.code)

    url: HttpUrl,
    header: String,
  ): List<Cookie> {
    val result = mutableListOf<Cookie>()
    var pos = 0
    val limit = header.length
    var pairEnd: Int
    while (pos < limit) {
      pairEnd = header.delimiterOffset(";,", pos, limit)
      val equalsSign = header.delimiterOffset('=', pos, pairEnd)
      val name = header.trimSubstring(pos, equalsSign)
      if (name.startsWith("$")) {

   * connection to an address fails, OkHttp will retry the connection with the next address until
   * either a connection is made, the set of IP addresses is exhausted, or a limit is exceeded.
   */
  @Throws(UnknownHostException::class)
  fun lookup(hostname: String): List<InetAddress>

  companion object {
    /**

 * or both.
 *
 * ## Authentication Retries
 *
 * If your authentication may be flaky and requires retries you should apply some policy
 * to limit the retries by the class of errors and number of attempts.  To get the number of
 * attempts to the current point use this function.
 *
 * ```java
 * private int responseCount(Response response) {
 *   int result = 1;

0002 0.554 responseBodyEnd
0002 0.554 connectionReleased
0002 0.554 callEnd
0001 0.624 responseBodyEnd
0001 0.624 connectionReleased
0001 0.624 callEnd
```

The `EventListener.Factory` also makes it possible to limit metrics to a subset of calls. This one captures metrics on a random 10%:

```java
class MetricsEventListener extends EventListener {
  private static final Factory FACTORY = new Factory() {

/**
 * Parse all headers delimited by "\r\n" until an empty line. This throws if headers exceed 256 KiB.
 */
class HeadersReader(val source: BufferedSource) {
  private var headerLimit = HEADER_LIMIT.toLong()

  /** Read a single line counted against the header size limit. */
  fun readLine(): String {
    val line = source.readUtf8LineStrict(headerLimit)
    headerLimit -= line.length.toLong()
    return line
  }

  request.url(url)

  data?.let {
    request.method(requestMethod, it.toRequestBody(mediaType()))
  }

  for (header in headers.orEmpty()) {
    val parts = header.split(':', limit = 2)
    if (!isSpecialHeader(parts[0])) {
      request.header(parts[0], parts[1])
    }
  }
  referer?.let {
    request.header("Referer", it)
  }
  request.header("User-Agent", userAgent)

        check(currentPart == this) { "closed" }

        source.timeout().intersectWith(timeout) {
          return when (val limit = currentPartBytesRemaining(maxResult = byteCount)) {
            0L -> -1L // No more bytes in this part.
            else -> source.read(sink, limit)
          }
        }

        error("unreachable") // TODO(jwilson): fix intersectWith() to return T.
      }

    case $MAX_FD in #(
      max*)
        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
        # shellcheck disable=SC2039,SC3045
        MAX_FD=$( ulimit -H -n ) ||
            warn "Could not query maximum file descriptor limit"
    esac
    case $MAX_FD in  #(
      '' | soft) :;; #(
      *)
        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.

   * limit: multiple hostnames may share an IP address or be routed through the same HTTP proxy.
   *
   * If more than [maxRequestsPerHost] requests are in flight when this is invoked, those requests
   * will remain in flight.
   *
   * WebSocket connections to hosts **do not** count against this limit.
   */
  var maxRequestsPerHost = 5
    get() = this.withLock { field }