code: public final static <T> Stream<T> onePer(final Stream<T> stream, final long time, final TimeUnit t) {
          return new OnePerOperator<>(
                                      stream).onePer(time, t);
      }
docs: emit one element per time period
  
  @see ReactiveSeq#onePer(long, TimeUnit)
  
  @param stream Stream to emit one element per time period from
  @param time  Time period
  @param t Time Pure
  @return Stream with slowed emission