Xero-node unable to download receipt attachments

//Create a local writestream
var wstream = fs.createWriteStream(tempFile, { encoding: 'binary' });

//Data has been written successfully
wstream.on('finish', function() {
    fs.readFile(tempFile, function (err, fsData) {
        // trigger upload to S3 function
        uploadToS3(req, {
            s3Path: s3Path,
            contentType: data.mime_type,
            buffer: fsData
        }, function (status, url) {
            data.url = '/' + data.url;
            fs.unlink(tempFile, function(err) {});
            callback();
        });
    });
});

wstream.on('error', function(err) {
    logErr(req, 'createUpdateAttachment: download data writing failed', [err]);
    wstream.close();
});

attachment.getContent(wstream)
.catch(function(err) {
    logErr(req, 'createUpdateAttachment: caught error during data writing', [err]);
});