Here are the classes, structs, unions and interfaces with brief descriptions:

Nwork
Ccontext	Borrowed owner-local submissions; valid only during its handler call. Children are accepted after close(): they belong to the already accepted task. Never share this context with another thread or retain it after the callback
Cgig	A typed, nonmovable lifetime boundary for submitted tasks and descendants. Each accepted task runs exactly once. close() is idempotent and rejects later external pushes; contexts may still create children. join() closes and waits for all descendants, publishing their writes to the caller. Destruction joins. push() and close() may race: the gig mutex determines whether push is accepted. The handler and all borrowed captures must remain valid until join returns
Cgig_options	Bound a gig's concurrency or keep all its callbacks on the joining caller
Cpool	Persistent workers shared by independent, overlapping typed gigs. The width includes one cooperating join caller; width one needs join() to make progress. A pool must outlive every gig made from it. Callbacks should not block waiting for other pool work: join() cooperates instead