otongithub / csharp-asyncawait

Following "Raw Coding" 2 videos covering C# Async Await.

Using .NET version 8.0.300-preview.24203.14

Commands

• dotnet new gitignore = dotnet new sln
• dotnet new console -lang "c#" -n "One" -f "net8.0" -o src/First/one -d -v diag
• dotnet new console -lang "c#" -n "Twi" -f "net8.0" -o src/First/two -d -v diag
• dotnet new console -lang "c#" -n "Three" -f "net8.0" -o src/First/three -d -v diag
• dotnet new web -lang "c#" -n "Second" -f "net8.0" -o src/Second -d -v diag
• dotnet sln add src/First/one
• dotnet sln add src/First/two
• dotnet sln add src/First/three
• dotnet sln add src/Second
• dotnet run --project src/Second

Notes

• Asynchrony process itself invovles letting another process handle it while doing some of its own work.
• To Run in VSCode, just press F5, if you have C# Extension Installed, and Have a working solution, should work.
• When Tasks and Async Awaits are needed are really when you need to do I/O bound tasks
  • like networking,
  • disk / database.
• As soon as async is called, a state machine is created, this can be seen in the IL code or use ILSpy to see the difference.
• Statemachine is like a class, and has points where code is awaited in the function, the variables become properties / states, and is saved in memory and not GC-ed.
• Don't make first reaction to change function async even if returning a Task/Promise.
  • Instead use something like Task.FromResult or Task.CompletedTask.
• As soon as tasks or async is used, it is propagated throughout the code.
  • I guess mostly if you are just waiting for something from a Task.