@Override
        public String toString() {
            return MoreObjects.toStringHelper(this)
                              .add("parent", parent)
                              .add("name", name)
                              .add("values", values)
                              .toString();
        }
Collects {@link PathVariable}s from the parsed {@link PathSegment}s.
grpc/src/main/java/com/linecorp/armeria/server/grpc/HttpJsonTranscodingService.java