How To Get Upload Progress Of A Uploading File With Dropbox Core API?

I'm currently using PHP + jQuery + Ajax to upload a file to my own dropbox account using localhost. I need to know how can I add a progressbar to this. Is there any way to do this? Currently I'm uploading files like this:

// all vars declared and initialized above

$result = $dbxClient->uploadFile("/{$userName}/{$_FILES['fileAttached']['name']}", dbx\WriteMode::add(), $file);

print_r($result);

// works like a charm.

But it doesn't let me know time remaining/upload progress. Any way to achieve it? Note: I'm using dropbox's CORE PHP API.