C#

What is boxing and provide an example of how it occurs? Which objects should be made into structures?

What is multithreading, what tasks does it solve, and what synchronization primitives do you know? How does SemaphoreSlim differ from Semaphore and what is a Mutex?

Is it possible to implement methods with bodies in a C# interface and why is it needed? What are the advantages over an abstract class?

What are the approaches to passing object state between services: state transfer/state sourcing and event sourcing?

Which REST API HTTP methods are idempotent? Is it possible to send requests/data in GET and what are the limitations? How do the 4xx and 5xx status code families differ?

What tasks are suitable for a monolith and how to smoothly evolve from it to microservices? What is a modular monolith?

What is sharding and what should be considered when designing it?

For what tasks is the 'using' construct in C# used, and what is it?

What is dependency injection, where is it used, and what are the available lifetimes: Transient, Scoped, Singleton?

What practical benefits does async/await provide in WinForms/WPF clients?

What is asynchronous programming, what tasks is it used for, and how does async/await work?

How to effectively implement a report with an average value over a period, if about a billion records are received daily in the table, and the total records are hundreds of billions?

What are Outbox and Inbox patterns?

Tell me about one or two tasks from your previous or current job that you are proud of.

What is IQueryable and when is the query executed?

// slice for all sensors, only the latest value by time // collection of anonymous objects, string double var result = list.GroupBy(x => x.Name) .Select(x => new { Name = x.Key, Value = x.OrderByDescending(g => g.Date).First().Value });

Which SQL operator is responsible for sorting when HAVING is used, and how do indexes help or hinder operations with the table?