LINQ performance best practices from production .NET: multiple enumeration, Count vs Any, allocation costs, and when a plain loop beats a query.
Diagnose and fix the EF Core N+1 query problem with Include, projections and split queries — plus how to catch lazy-loading traps before production.
Learn the most common async await C# mistakes — async void, .Result deadlocks, missing ConfigureAwait and more — with fixes from production code.