How to implement HTTP's beforeSend option

I’m using to download large files on for the client on occasion, and I’d like to show the progress to the user. I’ve implemented beforeSend, however, it simply does not execute the function. I’ve tried to more or less follow the structure used in Meteor’s test file short of not finding examples elsewhere:

Here is my implementation that does not work:

httpProgress = function(xhr) {
    console.log('I never see this');
    xhr.onprogress = function() {
        if (e.lengthComputable) {
            setProgress((e.loaded / * 100, 'downloading...', true);
            setProgress(-1, 'downloading...', true);
};'GET',url, {
        beforeSend: httpProgress,
        headers: {
            'Accept': '*/*'
        responseType: 'arraybuffer' //using aldeed:http here
    }, function(error, result) { 

The is executed fine, but my beforeSend function never runs. I’m stumped, any ideas? Thank you everyone.

In case anybody visits this with the same issue, as of this time aldeed:http does not support beforeSend. I’ve filed an issue on the package’s respective github repository.