anchor.diff:    external void addOnExitListener(SendPort responsePort, {Object response});
   
     /**
  -   * Stop listening on exit messages from the isolate.
  -   *
  -   * If a call has previously been made to [addOnExitListener] with the same
  -   * send-port, this will unregister the port, and it will no longer receive
  -   * a message when the isolate terminates.
  -   * A response may still be sent until this operation is fully processed by
  -   * the isolate.
  +   * Stop listening for exit messages from the isolate.
  +   *
  +   * Requests for the isolate to not send exit messages on [responsePort].
  +   * If the isolate isn't expecting to send exit messages on [responsePort],
  +   * because the port hasn't been added using [addOnExitListener],
  +   * or because it has already been removed, the request is ignored.
  +   *
  +   * If the same port has been passed via [addOnExitListener] more than once,
  +   * only one call to `removeOnExitListener` is needed to stop it from receiving
  +   * exit messagees.
  +   *
  +   * Closing the receive port at the end of the send port will not stop the
  +   * isolate from sending exit messages, they are just going to be lost.
  +   *
  +   * An exit message may still be sent if the isolate terminates
  +   * before this request is received and processed.
      */
     external void removeOnExitListener(SendPort responsePort);
   
  
positive.code:    *
     * * `IMMEDIATE`: The isolate responds as soon as it receives the
     *     control message. This is after any previous control message
     *     from the same isolate has been received, but may be during
     *     execution of another event.
     * * `BEFORE_NEXT_EVENT`: The response is scheduled for the next time
     *     control returns to the event loop of the receiving isolate,
     *     after the current event, and any already scheduled control events,
  
negative.code:   external void addErrorListener(SendPort port);
  
    /**
     * Stop listening for uncaught errors from the isolate.
     *
     * Requests for the isolate to not send uncaught errors on [responsePort].
     * If the isolate isn't expecting to send uncaught errors on [responsePort],
     * because the port hasn't been added using [addErrorListener],
     * or because it has already been removed, the request is ignored.
     *
     * If the same port has been passed via [addErrorListener] more than once,
     * only one call to `removeErrorListener` is needed to stop it from receiving
     * unaught errors.
     *
     * Closing the receive port at the end of the send port will not stop the
     * isolate from sending uncaught errors, they are just going to be lost.
     *
     * Uncaught errors message may still be sent by the isolate
     * until this request is received and processed.
     */
    external void removeErrorListener(SendPort port);
  
  