V checkValue(@ParametricNullness V value) {
    return value;
  }

  /**
   * Specifies the delegate maps going in each direction. Called by subclasses during
   * deserialization.
   */
  void setDelegates(Map<K, V> forward, Map<V, K> backward) {
    inverse = checkMapsAndMakeInverse(forward, backward);
    delegate = forward;
  }

   * connections.
   */
  private fun detachTimeout(timeout: ForwardingTimeout) {
    val oldDelegate = timeout.delegate
    timeout.setDelegate(Timeout.NONE)
    oldDelegate.clearDeadline()
    oldDelegate.clearTimeout()
  }

  /**
   * The response body from a CONNECT should be empty, but if it is not then we should consume it