extensions-review

Choose Singleton for stateless or immutable services, Scoped for state tied to a logical operation like a request, and Transient when a fresh instance is needed each time. Never inject a Scoped service into a Singleton, as that creates a captive dependency; use IServiceScopeFactory instead.

Avoid injecting scoped services directly into singletons. Instead, inject IServiceScopeFactory into the singleton, create an async scope on demand with CreateAsyncScope, and resolve the scoped service within that scope's lifetime.

Runtime configuration binding uses reflection and is not trim or AOT safe. For trimmed or AOT-published apps, use source-generated configuration binding and verify parity with the runtime binder for all bound types.

Use the [LoggerMessage] source generator for high-frequency log sites, as it provides zero-allocation logging. For infrequent logging, standard ILogger.Log{Level} calls with message templates are acceptable.

Blocking happens when synchronous work like reading all bytes runs before the first await. Use truly async APIs from the start, such as copying the input stream into a BrotliStream with CopyToAsync and honoring the cancellation token.

Use TryAdd methods for default service registrations in library extension methods. TryAdd only registers the service if no implementation is already registered, letting consumers override defaults without duplicate registrations.