What is async/await, why is it needed, and how does it unfold?

async and await are keywords in C# that allow you to write asynchronous code that looks like synchronous code, simplifying reading and maintenance.

• Why needed: Asynchrony allows not to block the execution thread during long operations (e.g., input/output, network requests), improving application responsiveness.

• How it works: Methods marked with async can contain await before calling tasks (Task), which pauses the method execution until the task completes but does not block the thread.

• What it unfolds into: The compiler transforms the asynchronous method into a state machine that manages the continuation after the awaited task completes.

Example:

public async Task<string> GetDataAsync()
{
    var result = await SomeLongRunningOperationAsync();
    return result;
}

Here, await pauses the method until SomeLongRunningOperationAsync completes, but the thread is not blocked.