default <A, B> Stream<Meta<A, B>> metaOn(
            Collection<A> models, Class<B> to) {
        
        return models.stream().flatMap(model -> metaOn(model, to));
    }
Renders all the specified models into a stream of code models. This is
used internally to provide the other interface methods.

@param <A>     the input type
@param <B>     the expected output type
@param models  the models to generate
@param to      the expected result type
@return        a stream of meta objects

@see Meta
common-parent/codegen/src/main/java/com/speedment/common/codegen/Generator.java