C# async, await and Task

How it works

A Task represents an operation that may complete later, while Task<T> can also carry a result. await lets an async method suspend until completion without requiring a blocked caller thread for that wait. The async keyword does not automatically move CPU work to another thread. I/O-bound APIs often already provide asynchronous methods; CPU-heavy work needs its own scheduling and resource policy. Keep asynchronous operations observable so failures reach a caller instead of disappearing in fire-and-forget work.

Run it locally

Use the .NET 10 SDK with C# 14 in a separate console lab. Create an empty project once with dotnet new console --framework net10.0, then replace Program.cs with this complete source and add any supporting files shown. Keep only one lesson entry point in the project. C# does not currently run in Bhylu’s browser playground. Apache, PHP and MySQL are not needed.

dotnet build -p:LangVersion=14.0 -p:Nullable=enable -p:TreatWarningsAsErrors=true
dotnet run --no-build

Use the SDK’s project workflow; the review compiles against its matching reference assemblies and executes the results without external NuGet packages. File-writing examples belong in a private empty lab directory.

Download the complete C# source as Program.cs.

Example

using System;
using System.Threading.Tasks;

internal static class Program
{
    private static async System.Threading.Tasks.Task Main(string[] args)
    {
        int places = await AvailableAsync();
        Console.WriteLine($"Available: {places}");
    }

    internal static async Task<int> AvailableAsync()
    {
        await Task.Yield();
        return 8;
    }
}

Expected result

Available: 8

Task.Yield creates a genuine asynchronous continuation boundary for this fixture, but it is not a simulated database call or a recommendation to add delay to ordinary calculations. The caller awaits before writing the result. In normal application code, avoid async void except for required event-handler signatures because its completion and exception handling are harder for callers to coordinate.