code: public SleepBuilder<T> withInterval(long interval, TimeUnit timeUnit) {
          this.interval = timeUnit.toMillis(interval);
          return this;
      }
docs: Interval is used by {@code SleepBuilder} to sleep between invocations of
  breaking condition.
  
  @param interval used to sleep between invocations of statement
  @param timeUnit of passed interval
  @return {@code SleepBuilder} with comparer