In what sense is fork/join more powerful than co-begin? What is a thread pool in Java? What purpose does it serve? What is meant by a two-level thread implementation? What is a ready list? Describe...

In what sense is fork/join more powerful than co-begin? What is a thread pool in Java? What purpose does it serve? What is meant by a two-level thread implementation? What is a ready list? Describe the progressive implementation of scheduling, preemption, and (true) parallelism on top of coroutines.