docs: @Override
      public Iterable<Object> loadAllKeys() {
          if (isMapLoader()) {
              Iterable<Object> allKeys;
              try {
                  allKeys = mapLoader.loadAllKeys();
              } catch (AbstractMethodError e) {
                  // Invoke reflectively to preserve backwards binary compatibility. Removable in v4.x
                  allKeys = ReflectionHelper.invokeMethod(mapLoader, "loadAllKeys");
              }
              return allKeys;
          }
          return null;
      }