@Override
    public List<ValidationEvent> evaluate(Differences differences) {
        return differences.addedShapes()
                .filter(shape -> shape.hasTrait(TraitDefinition.ID))
                .map(shape -> ValidationEvent.builder()
                        .id(getEventId())
                        .severity(Severity.NOTE)
                        .shape(shape)
                        .message(String.format("Trait definition `%s` was added", shape.getId()))
                        .build())
                .collect(Collectors.toList());
    }
Creates a NOTE event when a trait definition is added.
smithy-diff/src/main/java/software/amazon/smithy/diff/evaluators/AddedTraitDefinition.java