Returns the number of threads that have been spawned to service vertex paging requests, or 0 if no threads have been spawned (which may mean either that all paging requests will be handled by the main thread, or simply that no paging requests have yet been issued).
Returns the number of threads that have been spawned to service vertex paging requests, or 0 if no threads have been spawned (which may mean either that all paging requests will be handled by the main thread, or simply that no paging requests have yet been issued).