code: Set<Locale> getAllImplementationBoundLocales() {
          Set<Locale> res = new HashSet<Locale>();
          for (C10NImplementationBinder<?> binder : binders.values()) {
              res.addAll(binder.bindings.keySet());
          }
          return res;
      }
docs: <p>Get a set of all locales explicitly declared in implementation bindings
  
  @return set of all bound locales