Task Time Tracker while under one work session

Hello I am looking for individual task time tracking. What I mean by this is I do a variety of work and I also want to track the individual tasks so I can compared to my estimates. I would like if possible to just be able to have a running clock like a lap timer on a stopwatch where the main login will stay logged in but I can press a button and track the individual task separately. I think breaks are great and they should stay as they are, this would be an additional feature. This would make this app fantastic and I would pretty much keep it on me and as I change tasks I would keep updating my timers so in time my estimates will better reflect my actual performance.