void markShape(Shape shape) {
            if (sweepFilter.test(shape)) {
                markedForRemoval.add(shape);
                markedForRemoval.addAll(shape.members());
            }
        }
Marks a shape for removal.

@param shape Shape to remove.
smithy-model/src/main/java/software/amazon/smithy/model/transform/MarkAndSweep.java