csharp

Three ways to push work onto the thread pool in C#, and which one to reach for. Use Task.Run for almost everything, ThreadPool.QueueUserWorkItem<TState> for allocation-free fire-and-forget, and Task.Factory.StartNew only for LongRunning or a custom scheduler.

.NET 11 Preview 4 ships DeflateEncoder, GZipEncoder, and ZLibEncoder plus matching decoders so you can compress straight into a Span<byte> with OperationStatus, no Stream required.

C# 16 redesigns the unsafe keyword so it propagates a caller obligation instead of silently opening an unsafe context, with inner unsafe blocks now mandatory.

ConfigureAwait(false) is still mandatory in library code that may run under a SynchronizationContext (WinForms, WPF, MAUI). In application code on ASP.NET Core, a console app, or a worker service running on .NET 11, it is a no-op.

Three sequence interfaces, three execution models. Use IQueryable when a database can translate the query, IAsyncEnumerable when the producer is async and you want to stream, IEnumerable for everything else in memory.

async Task is the default and async void is the exception. Use async void only for event handlers, top-level message-loop handlers, and a handful of framework callbacks that demand a void signature. Everywhere else, async Task wins on exceptions, composition, and testability.

C# 14 gives you four data-type shapes -- class, record class, struct, and record struct. This is the decision matrix: when each one is correct, what each one costs, and the rules that pick for you.

After upgrading to C# 14 / .NET 10, calls like array.Contains, x.Reverse(), and MemoryMarshal.Cast suddenly bind to different overloads or stop compiling. Here is what changed and how to pin the old behaviour where it matters.

The .NET 6 runtime is gone or mismatched. Either install net6.0 again, roll forward to net8.0 via runtimeconfig, retarget the csproj, or ship self-contained.

.NET 11 Preview 4 bundles the mcpserver project template directly into the SDK. No separate Microsoft.McpServer.ProjectTemplates install, no preview feed dance. Pick stdio or HTTP transport, opt into Native AOT, and dotnet new mcpserver -o MyServer is the whole setup.