I’ve always wanted to do something like

class URLSessionDataTask_Plus: URLSessionDataTask {
    
    var obs: NSKeyValueObservation? = nil
    // store the progress observer there 
}

which would be very convenient. I don’t know how to do it. If instead you do something like

///URLSessionDataTask, plus more!
class URLSessionDataTask_Plus {
    
    var task: URLSessionDataTask? = nil
    var obs: NSKeyValueObservation? = nil
}

there’s really no advantage, as you anyway have to still maintain that variable externally (or maintain that whole object externally).

Progress observations are a real nuisance to hang on to as you never know how many you’ll need or where.

Is there some way to achieve this concept? ->

class URLSessionDataTask_Plus: URLSessionDataTask {
    
    var obs: NSKeyValueObservation? = nil
    // store the progress observer there 
}

(I note that the same applies even if you use the futuristic async calls .. /a/78804162/294884 )