Hub methods with progress support

client.js

$.connection.hub.start().done(function() {
    var hub = $.connection.myHub;
    
    hub.server.doLongRunningThing()
        .progress(function(p) {
            console.log("Long running thing: " + p + "%");
        })
        .done(function() {
            console.log("Long running thing complete!");
        })
        .fail(function(e) {
            console.log("Long running thing failed: "  + e.message);
        });
});

MyHub.cs

public class MyHub : Hub
{
    // The hub method must be Task returning and accept an IProgress<T>
    public async Task DoLongRunningThing(IProgress<int> progress)
    {
        for (var i = 0; i <= 100; i+=5)
        {
            await Task.Delay(200);
            progress.Report(i);
        }
    }
}

@drub0y the progress reporting is 1:1 to the method caller. It's supposed to represent progress of the method duration, so you can't report progress after the method has returned (it throws). This is now implemented in a feature branch (https://github.com/signalr/signalr/tree/feature-2380-hub-progress) if you're interested.