static <A> A shallowCloneToClassWithFields(Class<A> c, O o, S... fields) {
  if (o == null) null;
  A a = nuInstance(c);
  copyFields(o, a, fields);
  ret a;
}

static <A> A shallowCloneToClassWithFields(O o, Class<A> c, S... fields) {
  ret shallowCloneToClassWithFields(c, o, fields);
}

static <A> A shallowCloneToClassWithFields(Class<A> c, O o, Cl<S> fields) {
  ret shallowCloneToClassWithFields(c, o, toStringArray(fields));
}