Visug The Visual Studio User Group



Internals of Async

Async and await are now common elements of .NET ecosystem. Do you know how they work? Do you know what is synchronization context, how to wait for async void methods or how to implement custom task scheduler?

In this talk, I show internals of async and await. I present state machine created by the compiler, consider allocation issues and show typical deadlock scenarios. We will see how to call async methods from synchronous code, how to wait for async void, how to implement custom synchronization context or task scheduler to handle exceptions, and how to run task without allocation at all.

Level 400, very intense session.

Learning Objectives:

  • Understanding state machine generated by the compiler
  • Learning details of TPL and synchronization contexts
  • Debugging common deadlock scenarios
Adam Furmanek

I am Adam Furmanek and I am a professional software engineer for almost a decade. Right now I am at Amazon working with Big Data, Spark, and Machine Learning. I am always interested in digging deeper, exploring machine code and going through implementation details to better understand internals of the technologies I use every day. That's why I like debugging, decompiling and disassembling the code to understand memory models, concurrency problems and other details hidden deeply inside. In my free time I play ping-pong, watch Woody Allen's movies and blog stuff at


Practical information

Location: virtual