private static void detectShapeChanges(Model oldModel, Model newModel, Differences differences) {
        for (Shape oldShape : oldModel.toSet()) {
            newModel.getShape(oldShape.getId()).ifPresent(newShape -> {
                if (!oldShape.equals(newShape)) {
                    differences.changedShapes.add(new ChangedShape<>(oldShape, newShape));
                }
            });
        }
    }
Gets a stream of all changed metadata.

@return Returns the changed metadata.
smithy-diff/src/main/java/software/amazon/smithy/diff/Differences.java