code: private static Duration create(long seconds, int nanoAdjustment) {
          if ((seconds | nanoAdjustment) == 0) {
              return ZERO;
          }
          return new Duration(seconds, nanoAdjustment);
      }
docs: Obtains an instance of {@code Duration} using seconds and nanoseconds.
  
  @param seconds  the length of the duration in seconds, positive or negative
  @param nanoAdjustment  the nanosecond adjustment within the second, from 0 to 999,999,999