docs: public static String abbreviate(ChronoUnit unit) {
          switch (unit) {
              case NANOS:
                  return "ns";
              case MICROS:
                  return "\u03bcs"; // μs
              case MILLIS:
                  return "ms";
              case SECONDS:
                  return "s";
              case MINUTES:
                  return "m";
              case HOURS:
                  return "h";
              case DAYS:
                  return "d";
              default:
                  throw new AssertionError("Unexpected time unit: " + unit);
          }
  
      }