default Optional<? extends Index> findIndex(String id) {
        return indexes().filter(child -> child.getId().equals(id)).findAny();
    }
Locate the {@link Index} child with the specified id if it exists, else
return an empty {@code Optional}.

@param id  the {@link HasId#getId()} of the index
@return    the child found or an empty {@code Optional}
runtime-parent/runtime-config/src/main/java/com/speedment/runtime/config/Table.java