In the .NET world, async and await are fundamental, and Tasks are at the core of this. However, the Task type is often seen as magical, with many developers unaware of the underlying mechanics. In this talk, we will step back and build our own Task and ThreadPool from scratch, examining how they interact with each other to enable imperative asynchronous programming.

By deconstructing these foundational components, we’ll explore how asynchronous code really works under the hood. You'll come away with a deeper, more practical understanding of Task-based asynchronous programming — which could come in handy for your next debugging session.

This is a live coding session where I create a Task implementation from scratch while explaining details.

The talk is targeted for intermediate level developers (200), but I think even most expert level developers have some things to learn.

I held this talk at ADC2025 in Regensburg and at the Dotnet Day Franken 2025, where it received the Best Session Award.

If I submitted multiple talks and you are not sure which one to choose: This is currently my favourite talk.