如何使用屏幕外文档在自定义 chrome 扩展程序中下载 PDF

问：

由于我生成的 PDF 的大小，base64 转换是不可能的，我必须使用屏幕外功能。

基于这个答案 -> https://stackoverflow.com/a/75539867/8016254

我尝试下载一个 PDF 文件，该文件将在我的自定义 chrome 扩展程序中重新定义。

background.js

import './pdf-lib.min.js';

chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
    (async () => {
        if (message.pdfUrls && message.pdfUrls.length > 0) {
            // Debug PDF
            const urls = ["https://www.africau.edu/images/default/sample.pdf"];
            await mergeAllPDFs(urls, "Test");
        }
    })();

    return true;
});
async function mergeAllPDFs(urls, filename) {
    const numDocs = urls.length;
    const pdfDoc = await PDFLib.PDFDocument.create();
    for (let i = 0; i < numDocs; i++) {
        console.log(`Fetching ${urls[i]}`)
        const donorPdf = await fetch(urls[i]);
        const donorPdfBytes = await donorPdf.arrayBuffer();
        const donorPdfDoc = await PDFLib.PDFDocument.load(donorPdfBytes);
        const copiedPages = await pdfDoc.copyPages(donorPdfDoc, donorPdfDoc.getPageIndices());
        copiedPages.forEach((page) => pdfDoc.addPage(page));
    }
    const pdfDocBytes = await pdfDoc.save();
    const waiting = await chrome.offscreen.createDocument({
        url: 'offscreen.html',
        reasons: ['BLOBS'],
        justification: 'reason for needing the document',
    });
    chrome.runtime.sendMessage({
        data: pdfDocBytes
    }, (response) => {
        console.log(response);
        const url = response.url;
        console.log(url);
        chrome.downloads.download({
            url: url,
            filename: filename + ".pdf"
        });
    });

}

offscreen.js

chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
    const blob = new Blob([message.data], { type: "application/pdf" });
    const url = URL.createObjectURL(blob);
    sendResponse({ url: url });
    return true;
});

生成的 PDF 似乎已损坏，并且比预期的要小得多。有什么想法吗？