将RMarkdown :: Render放在ShinyApp的未来函数中

Question

我有一个闪亮的应用程序，需要在'future'函数中放置RMarkdown :: render，以便其他用户在RMD加载/渲染时继续使用该应用程序。运行应用程序并单击下载按钮时，以下代码可用。但是，当我取消注释新代码，实现未来并运行应用程序时，我收到错误“找不到对象'params'。”

output$snapshot_report_pdf_download <- downloadHandler( 

      filename = function() {
        if(trimws(input$snap_print_pdf_save_name,"both") == "") {
          "Portfolio Snapshot Report.pdf"
        } else {
          paste0(input$snap_print_pdf_save_name, ".pdf")              
        }
      },

      content = function(file){
        params <- list(
          ohf_sh_obj = ohf_sh_obj,
          data_date = ohf_sh_obj$data_date,
          report = "portfolio_snapshot",
          graph = input$snap_print_graphs,
          wl_selection_snap = input$wl_selection_snap,
          date_selection_snap = input$date_selection_snap,
          stacked_snap = input$stacked_snap
           )

        out <- render('scripts/printing/report_pdf.rmd')

        file.rename(out, file)

        if (file.exists("scripts/printing/report_pdf.rmd")) {
          file.remove("scripts/printing/report_pdf.rmd")
         }

        # future({render('scripts/printing/report_pdf.rmd',
        #                params = params)},
        #        globals = T,
        #        packages = c("knitr", "rmarkdown")) %...>%
        #   (function(result) {
        #     file.rename(result, file)                
        }
      })

非常感谢任何帮助。