set fps(fps) {
    this._fps = fps;
    this._interval = fps === "auto" ? Proton.DEFAULT_INTERVAL : MathUtil.floor(1 / fps, 7);
  }
Sets the frames per second (FPS) for the Proton system.
@param {number|string} fps - The desired FPS. Use "auto" for default behavior, or a number for a specific FPS.