Method once

out/cli.cjs:70331–70335

* Adds a one-time listener function for the event. The next time the event is triggered, * this listener is removed and then invoked. * @returns this MessageStream, so that calls can be chained

(event, listener)

      listeners.splice(index, 1);
    return this;
  }
  /**
   * Adds a one-time listener function for the event. The next time the event is triggered,
   * this listener is removed and then invoked.
   * @returns this MessageStream, so that calls can be chained
   */
  once(event, listener) {
    const listeners = __classPrivateFieldGet7(this, _MessageStream_listeners, "f")[event] || (__classPrivateFieldGet7(this, _MessageStream_listeners, "f")[event] = []);