private Collection<? extends Shape> getStartingShapes(Model model, StartingContext startingContext) {
        Collection<? extends Shape> startingShapes = startingContext.getStartingShapes();
        return startingShapes == null ? delegate.getStartingShapes(model) : startingShapes;
    }
Uses parallel streams when the model size exceeds this number.
smithy-model/src/main/java/software/amazon/smithy/model/selector/WrappedSelector.java