Public subclasses of {@link galois.runtime.wl.Worklist} are intended to be the class arguments to the {@link galois.runtime.wl.Priority#first(Class, Object...)}, {@link galois.runtime.wl.Priority.Rule#then(Class, Object...)}, and {@link galois.runtime.wl.Priority.Rule#thenLocally(Class, Object...)} methods. @see galois.runtime.wl.Priority