ExchangeRateProvider that delegates calls to
a collection of child ExchangeRateProvider instance.Currency into the
MonetaryCurrencies singleton either by currency code, locale, or both.BuildableCurrencyUnit.BuildableCurrencyUnit and publishes it so it is
accessible from the MonetaryCurrencies singleton.BuildableCurrencyUnit and publishes it so it is
accessible from the MonetaryCurrencies singleton.MonetaryAmount, using the default MonetaryContext.