The journey of every round

Write a generic Swap<T> method that swaps two ref T parameters. Include an example call with two ints.

Write an xUnit IClassFixture<T> that spins up a TestServer once per test class and exposes an HttpClient to the tests. Show one test using it.

Build a TPL Dataflow pipeline: a TransformBlock that parses lines from a file, an ActionBlock that writes results to disk, linked with bounded capacity 100.

Configure Serilog with a console sink and a file sink that rolls daily. Include a custom enricher (ILogEventEnricher) that adds the machine name to every log event.

Register a typed HttpClient with IHttpClientFactory for calling a remote API, including a DelegatingHandler that adds an Authorization bearer token to every request.

Implement a multitenant request-scoped ITenantInfo resolver that reads the tenant id from a custom header and falls back to subdomain.

Use Microsoft.FeatureManagement feature flags to gate a new checkout flow. Show the IFeatureManager check at the controller level and the flag definition in configuration.

Add OpenTelemetry tracing to an existing service. Show creating an ActivitySource, starting a child Activity around a database call, and tagging it with the query name.

Build a producer-consumer pair using Channel<T>: producer emits work items at 100/sec; consumer processes them with bounded backpressure (max 50 in-flight).

Define a gRPC service in protobuf with one bidirectional streaming method that echoes back messages with a server-side timestamp. Show the server-side service implementation.

Build a SignalR Hub that lets clients subscribe to a 'price-tick' channel and broadcasts ticks to all subscribers on a one-second timer.

Configure structured logging using ILogger<T>. Show a service that injects ILogger<MyService> and writes a log scope around a unit of work, including a correlation id.

Build a Polly v8 ResiliencePipeline that retries on transient HTTP errors three times with exponential backoff, then trips a circuit breaker after five consecutive failures.

Bind a 'SmtpSettings' section from configuration using the options pattern with IOptionsMonitor so values update when the config file changes at runtime.

Write a FluentValidation AbstractValidator<T> for a 'RegisterUser' command: email (valid format), password (≥ 8 chars, has digit and symbol), age (18+).

Implement a generic repository for read-only access to entities by id using a DbContext. Include AsNoTracking and a CancellationToken parameter.

Define a DbContext with two entities (Order and Customer) related one-to-many. Show the OnModelCreating configuration and a simple query that loads orders with their customer.

Set up a RabbitMQ consumer that subscribes to an 'orders.created' queue. Show the publish call from the order service side.

Write a MediatR IRequestHandler<TRequest,TResponse> for a 'GetUserById' query, plus an IPipelineBehavior that writes the request type name to console before invoking the next handler.

Implement cache-aside using IDistributedCache backed by Redis to memoise an expensive lookup that returns a customer profile.

Write a BackgroundService that reads work items from an in-memory queue and processes each one with a small delay, with graceful shutdown handling.

Configure JwtBearer authentication so tokens are accepted from either the Authorization header or a query string parameter. Include the validation parameters.

Implement an IAuthorizationHandler for a 'CanEditOwn' permission that checks the current user owns the resource being modified.

Implement an IHealthCheck that returns Healthy when a TCP socket on a remote host responds within 500ms, and Unhealthy otherwise.