35 Senior .NET Developer Interview Questions That Actually Get Asked…

Inside PGO

In the previous article , we made Go code faster by changing how it computes. SIMD lets one CPU instruction work on several values at once, and the simd/archsimd and simd packages give Go access to it. Our dot product ran about 9 times faster, but the code got a lot harder to read. At the end, I promised another route to speed, one where you don’t rewrite anything. That route is Profile-Guided Optimization (PGO). You record a CPU profile of where your program spends its time and give it back to the compiler, so it can work harder on the code that is actually hot. Your source stays exactly as it was. We briefly saw it in the IR post , and today we’re going deep into it.

Vercel Sandbox snapshot creation is now up to 10x faster

Vercel Sandbox snapshots now use an optimized indexing format, cutting median creation time from 4.4s to under 0.4s.

How to Implement HTTP Resilience Without Polly in .NET 10

Polly's maintenance fee starts 16 November 2026. See who pays, the free Microsoft route, Kevlar, and a tested Polly-free retry and circuit breaker in .NET 10.

Outbox Pattern in .NET With Postgres: Concurrent Workers vs the WAL

An API can save an order and crash before publishing the message that tells other services about it.

HttpClient in .NET 10 - IHttpClientFactory and Resilience

Use HttpClient in .NET 10 with IHttpClientFactory, keyed and typed clients, and AddStandardResilienceHandler, with real socket and POST retry test results.

What happens to a method that awaits forever?

What happens if you await something that never finishes? Does the method sit in memory until the heat death of the universe (or all the other possible scenarios)? Does it leak? Let's find out, and then do some things you should definitely 100% legit do in production.

How to Loop Through a List in C#: Every Way, Benchmarked

How to loop through and iterate a List<T> in C# with foreach, for, ForEach, Index(), and spans, plus break, continue, safe removal, and benchmarks.

Microsoft.UI.Reactor: a C#-first way to build WinUI apps

Microsoft.UI.Reactor là một framework C# để phát triển ứng dụng WinUI, ra mắt tại Microsoft Build 2026. Framework này giải quyết vấn đề hiệu năng khi render UI bằng cách implement virtual DOM pattern tương tự React. Thử nghiệm cho thấy UI.Render cải thiện 30% tốc độ so với WinUI truyền thống. Điều đáng học hỏi là cách tiếp cận hybrid này kết hợp ưu điểm của C# với pattern từ frontend JavaScript. Bạn nên đọc bài gốc nếu đang tìm cách tối ưu hóa hiệu năng cho ứng dụng WinUI của mình.

Microsoft.UI.Reactor mang đến cách tiếp cận đơn giản hóa và hiệu quả hơn để phát triển ứng dụng WinUI bằng C#.