使用node的fs复制pdf会产生不同的文件

const { PDFDocument } = require('pdf-lib');
const fs = require('fs');

async function copyPDF(sourcePath, destinationPath) {
  const sourcePDFBytes = await fs.promises.readFile(sourcePath);
  const sourcePDF = await PDFDocument.load(sourcePDFBytes);

  const destinationPDF = await PDFDocument.create();
  const copiedPages = await destinationPDF.copyPages(sourcePDF, sourcePDF.getPageIndices());
  copiedPages.forEach((page) => destinationPDF.addPage(page));

  const destinationPDFBytes = await destinationPDF.save();
  await fs.promises.writeFile(destinationPath, destinationPDFBytes);
}

const sourcePath = 'path/to/source.pdf';
const destinationPath = 'path/to/destination.pdf';

copyPDF(sourcePath, destinationPath)
  .then(() => console.log('PDF file copied successfully'))
  .catch((error) => console.error('Failed to copy PDF file:', error));