getBufferedMaxExtent() {
    if (!this.bufferedMaxExtent_) {
      this.bufferedMaxExtent_ = clone(this.maxExtent);
      if (this.maxLineWidth > 0) {
        const width = (this.resolution * (this.maxLineWidth + 1)) / 2;
        buffer(this.bufferedMaxExtent_, width, this.bufferedMaxExtent_);
      }
    }
    return this.bufferedMaxExtent_;
  }
Get the buffered rendering extent.  Rendering will be clipped to the extent
provided to the constructor.  To account for symbolizers that may intersect
this extent, we calculate a buffered extent (e.g. based on stroke width).
@return {import("../../extent.js").Extent} The buffered rendering extent.
@protected