The call stack is a part of memory that is allocated by a thread or a coroutine and contains a stack of functions that were invoked in the context of the thread and local variables.
Thread pool is a pattern that uses a set of threads that are waiting for a job from a queue.
Callback is a pattern used for delivering the result of an asynchronous operation.
Coroutines are lightweight threads, because the creation of a coroutine doesn't require as many resources as the creation of a thread.
