code: public final int getOffset(ReadableInstant instant) {
          if (instant == null) {
              return getOffset(DateTimeUtils.currentTimeMillis());
          }
          return getOffset(instant.getMillis());
      }
docs: Gets the millisecond offset to add to UTC to get local time.
  
  @param instant  instant to get the offset for, null means now
  @return the millisecond offset to add to UTC to get local time