stream.defaultReadObject();
    keyTypeOrObjectUnderJ2cl = (Class<K>) requireNonNull(stream.readObject());
    valueTypeOrObjectUnderJ2cl = (Class<V>) requireNonNull(stream.readObject());
    setDelegates(
        new EnumMap<>(keyTypeOrObjectUnderJ2cl), new EnumMap<>(valueTypeOrObjectUnderJ2cl));
    Serialization.populateMap(this, stream);
  }

     * the number of entries in the map, as that makes it easy for hostile inputs to trigger lots of
     * allocation—not that any program should be deserializing hostile inputs to begin with!)
     */
    setDelegates(new EnumMap<>(keyTypeOrObjectUnderJ2cl), new HashMap<>());
    Serialization.populateMap(this, stream);
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

  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