/**
   * Returns null if any label is oversized so much that the encoder cannot encode it without
   * integer overflow. This will not return null for labels that fit within the DNS size
   * limits.
   */
  fun encode(string: String): String? {
    var pos = 0
    val limit = string.length
    val result = Buffer()

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

      this.withLock {
        field = maxRequests
      }
      promoteAndExecute()
    }

  /**
   * The maximum number of requests for each host to execute concurrently. This limits requests by
   * the URL's host name. Note that concurrent requests to a single IP address may still exceed this
   * limit: multiple hostnames may share an IP address or be routed through the same HTTP proxy.
   *

    `DurationUnit` which was a typealias in 1.5.x.
 *  Upgrade: [Okio 3.2.0][okio_3_2_0].


## Version 5.0.0-alpha.9

_2022-06-16_

 *  New: Enforce label length limits in URLs. `HttpUrl` now rejects URLs whose domains aren't valid.
    This includes overly-long domain names (longer than 253 characters), overly-long labels (more
    than 63 characters between dots), and empty labels.