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.
if (this.pdfLoadingTask) {
      
      await this.close();
    }
    
    const workerParameters = AppOptions.getAll(OptionKind.WORKER);
    for (const key in workerParameters) {
      GlobalWorkerOptions[key] = workerParameters[key];
    }
    const parameters = Object.create(null);
    if (typeof file === "string") {
      
      this.setTitleUsingUrl(file);
      parameters.url = file;
    } else if (file && "byteLength" in file) {