* including dots after the first colon. It matches IPv4 addresses as strings containing only
 * decimal digits and dots. This pattern matches strings like "a:.23" and "54" that are neither IP
 * addresses nor hostnames; they will be verified as IP addresses (which is a more strict
 * verification).
 */
private val VERIFY_AS_IP_ADDRESS = "([0-9a-fA-F]*:[0-9a-fA-F:.]*)|([\\d.]+)".toRegex()

    shares connections when hosts share both IP addresses and certificates, such as `squareup.com`
    and `www.squareup.com`. If a server refuses such sharing it will return HTTP 421 and OkHttp will
    automatically retry on an unshared connection.
 *  Fix: Don't crash if a TLS tunnel's response body is truncated.
 *  Fix: Don't track unusable routes beyond their usefulness. We had a bug where we could track

   */
  class AddressPolicy(
    /**
     * How many concurrent calls should be possible to make at any time.
     * The pool will routinely try to pre-emptively open connections to satisfy this minimum.
     * Connections will still be closed if they idle beyond the keep-alive but will be replaced.
     */
    @JvmField val minimumConcurrentCalls: Int = 0,

   * [requestBodyOpen], [responseBodyOpen], and [expectMoreExchanges].
   *
   * This will release the connection if it is still held.
   *
   * It will also notify the listener that the call completed; either successfully or
   * unsuccessfully.
   *
   * If the call was canceled or timed out, this will wrap [e] in an exception that provides that
   * additional context. Otherwise [e] is returned as-is.
   */

 *
 * Implementations of this interface must be safe for concurrent use.
 */
fun interface Dns {
  /**
   * Returns the IP addresses of `hostname`, in the order they will be attempted by OkHttp. If a
   * 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)

    // Create a payload which will overflow the normal payload byte size.
    val payload = Buffer()
    while (payload.completeSegmentByteCount() <= PAYLOAD_BYTE_MAX) {
      payload.writeByte('0'.code)
    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.

 * header, or they may decline the challenge by returning null. In this case the unauthenticated
 * response will be returned to the caller that triggered it.
 *
 * Implementations should check if the initial request already included an attempt to
 * authenticate. If so it is likely that further attempts will not be useful and the authenticator
 * should give up.
 *

     *
     * In this case the bytes are immediately copied into [sink] and the number of bytes copied is
     * returned.
     *
     * If upstream would be selected but another thread is already reading upstream this will
     * block until that read completes. It is possible to time out while waiting for that.
     */
    @Throws(IOException::class)
    override fun read(
      sink: Buffer,
      byteCount: Long,
    ): Long {

   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,
   * including any potential composed values.
   *
   * If there's nothing to read and no default value, this will throw an exception.
   */
  fun fromDer(reader: DerReader): T

  fun fromDer(byteString: ByteString): T {
    val buffer = Buffer().write(byteString)
    val reader = DerReader(buffer)
    return fromDer(reader)

  fun interface Factory {
    /**
     * Creates a new event source and immediately returns it. Creating an event source initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must cancel the returned event source when it is no longer in use.
     */
    fun newEventSource(
      request: Request,
      listener: EventSourceListener,
    ): EventSource
  }