code: public static ResourceKey key(Enum<?> enumValue, String key) {
          return new ResourceKey(enumValue.getClass().getName(), enumValue.name()).child(key);
      }
docs: Creates a resource key defined as a child of key defined by enumeration value.
  @see #key(Enum)
  @see #child(String)
  @param enumValue the enumeration value defining the parent key
  @param key the child id
  @return the resource key