code: public static Iterable<Measurement> filter(
        final Iterable<Measurement> ms, final Predicate<Measurement> p) {
      return () -> new FilteredIterator<>(ms.iterator(), p);
    }
docs: Returns a new iterable restricted to measurements that match the predicate.
  
  @param ms
  A set of measurements.
  @param p
  Predicate to use for selecting values.
  @return
  Measurements matching the predicate.