public Set<ValidationEvent> determineResolvedEvents() {
            Set<ValidationEvent> events = new TreeSet<>(getOldModelEvents());
            events.removeAll(getNewModelEvents());
            return events;
        }
Gets the validation events that were present in the old model but
are no longer an issue in the new model.

@return Returns the resolved validation events.
smithy-diff/src/main/java/software/amazon/smithy/diff/ModelDiff.java