@Override
                public Relationship next() {
                    if (current == null) {
                        throw new NoSuchElementException();
                    }
                    Relationship result = current.value;
                    current = current.next;
                    return result;
                }
An immutable {@code Relationship} path from a starting shape to an end shape.
smithy-model/src/main/java/software/amazon/smithy/model/selector/PathFinder.java