code: public long getStartTime(TimeUnit unit) {
          // FIXME use BigInteger representation
          long totalNanos = TimeUnit.SECONDS.toNanos(startTime.getEpochSecond());
          totalNanos += startTime.getNano();
          return unit.convert(totalNanos, TimeUnit.NANOSECONDS);
      }
docs: Returns the desired start time position in the requested units.
  
  @param unit the unit of time
  @return the desired start time position