Since #12241 we have notifications for this when the user navigates away from the viewer, but we do not yet warn when switching documents, which means that if you call e.g. `PDFViewerApplication.open` with a new document (or directly call `BaseViewer.setDocument` when using the viewer components standalone) there won't be any warning about losing form data. This should be addressed.
this.pdfRenderingQueue.printing = !!this.printService;
    this.pdfRenderingQueue.isThumbnailViewEnabled = this.pdfSidebar.isThumbnailViewVisible;
    this.pdfRenderingQueue.renderHighestPriority();
  },
  beforePrint() {
    
    
    this.pdfScriptingManager.dispatchWillPrint();
    if (this.printService) {
      
      
      
      return;
    }
    if (!this.supportsPrinting) {
      this.l10n.get("printing_not_supported").then(msg => {
        this._otherError(msg);
      });
      return;
    }