Tag: comparison

List<T> is a growable heap collection; Span<T> and ReadOnlySpan<T> are stack-only views over memory you already own. Use List<T> for anything you store, return from async, or grow; Span<T> for a mutable allocation-free view in a synchronous method; ReadOnlySpan<T> for read-only parsing over strings, u8 literals, and slices.

Use Parallel.ForEach for CPU-bound work over in-memory data, Parallel.ForEachAsync for async I/O over many items with a concurrency cap, and Task.WhenAll for a small fixed fan-out where you want every operation in flight and need the results back.

Use string interpolation for one-shot composition of a fixed set of values; use StringBuilder when you append in a loop or across an unknown number of pieces. The dividing line is the loop, not the number of values.

Four ways to guard a critical section in C#, and a decision matrix for picking one. Use System.Threading.Lock for synchronous mutual exclusion on .NET 9+, SemaphoreSlim when the section spans an await, and Monitor only when you need Wait/Pulse.

Use the Microsoft.Extensions.Http.Resilience handler for HttpClient calls, since it is Polly with HTTP-aware defaults and telemetry in one line. Reach for Polly's ResiliencePipeline directly only when you protect something that is not an HttpClient.

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.

For read-heavy paths in .NET 11, plain EF Core with AsNoTracking is within ~5% of Dapper. Reach for compiled queries on a profiled single-row hot path, and Dapper only for the lowest latency or SQL LINQ can't express.

Never new up HttpClient per request. Use IHttpClientFactory to manage lifetime, and add Refit on top when you want a typed interface instead of hand-written request code. Raw singleton HttpClient is fine only for the simplest cases.

For new code, plain service classes are the better default. MediatR's July 2025 license change matters only if you sit above the $5M Community threshold or refuse the RPL-1.5 copyleft. Keep MediatR when pipeline behaviors are load-bearing.

Plain JIT with Dynamic PGO wins steady-state throughput, ReadyToRun cuts startup with zero code changes, and Native AOT gives the smallest, fastest-starting binary at the cost of reflection and dynamic code. Pick by deployment shape, not raw benchmarks.