code: private static String coerceToEpoch(String s) {
  		Long epoch = parseEpochSecond(s);
  		if (epoch != null) {
  			return String.valueOf(epoch);
  		}
  		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");
  		try {
  			return String.valueOf(format.parse(s).getTime());
  		}
  		catch (ParseException ex) {
  			return s;
  		}
  	}
docs: Attempt to convert the specified value to epoch time. Git properties information
  are known to be specified either as epoch time in seconds or using a specific date
  format.
  @param s the value to coerce to
  @return the epoch time in milliseconds or the original value if it couldn't be
  converted