What is the thread pool in .NET?

The .NET thread pool maintains reusable worker threads for executing short-lived work. Tasks, timers, asynchronous continuations, and many framework operations use thread-pool infrastructure.

Reusing threads is more efficient than creating a new operating-system thread for every operation.

Blocking thread-pool threads for long periods can cause thread-pool starvation, increasing request latency. In scalable server applications, asynchronous I/O helps avoid consuming threads while waiting for external resources.