public Set<ResourceShape> getContainedResources(ToShapeId entity) {
        return resources.getOrDefault(entity.toShapeId(), SetUtils.of());
    }
Get all resources in a service or resource closure.

@param entity Service or resource shape ID.
@return Returns all resources in the service closure.
smithy-model/src/main/java/software/amazon/smithy/model/knowledge/TopDownIndex.java