docs: private static MonetaryRoundingsSingletonSpi monetaryRoundingsSingletonSpi() {
          try {
              return Optional.ofNullable(Bootstrap
                      .getService(MonetaryRoundingsSingletonSpi.class))
                      .orElseGet(DefaultMonetaryRoundingsSingletonSpi::new);
          } catch (Exception e) {
              Logger.getLogger(Monetary.class.getName())
                      .log(Level.SEVERE, "Failed to load MonetaryCurrenciesSingletonSpi, using default.", e);
              return new DefaultMonetaryRoundingsSingletonSpi();
          }
      }