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.
spreadMode = apiPageLayoutToSpreadMode(pageLayout);
          }
          this.setInitialView(hash, {
            rotation,
            sidebarView,
            scrollMode,
            spreadMode,
          });
          this.eventBus.dispatch("documentinit", { source: this });
          
          
          if (!this.isViewerEmbedded) {
            pdfViewer.focus();
          }
          
          
          this._initializePermissions(pdfDocument);
          
          
          
          
          
          await Promise.race([
            pagesPromise,
            new Promise(resolve => {
              setTimeout(resolve, FORCE_PAGES_LOADED_TIMEOUT);
            }),
          ]);
          if (!initialBookmark && !hash) {
            return;