File Streams Not Closing on appendPage

[stormflurry]

Hi, I've run into a bug where file streams are not closing on using appendPage.

// create a merged pdf                    
var pdfDoc = new HummusRecipe('new', appRoot + '\\labels\\full_' + params.orderId + '.pdf');
    for (p=0; p<pdfFiles.length; p++){     
        pdfDoc.appendPage(pdfFiles[p], p).endPage();
        }                          
await pdfDoc.endPDF();

I immediately do a cleanup on the files that were merged into one and each time the last file merged files to unlink() properly because it's file stream is still open and not properly cleaned up by hummus-recipe.

If I add a pause of 1000 ms then it fixes the error but something is not immediately releasing the file stream after .endPage().

Please fix this bug.

[PhakornKiong]

The bug is still reproducible if I do the following

const pdfDoc = new HummusRecipe(inputPath, outputPath);
pdfDoc.encrypt(option).endPDF(() => {});
    
fs.unlink(inputPath) // Error: EBUSY: resource busy or locked, unlink

Somehow a pause of 1000ms as reported is not working for me, I need to do nearly 10000ms for it to works.

const pdfDoc = new HummusRecipe(inputPath, outputPath);
pdfDoc.encrypt(option).endPDF(() => {});
    
setTimeout(() => {
  fs.unlink(inputPath);
}, 10000);