code: public static ConversionContext of(String provider, RateType rateType) {
          ConversionContextBuilder b = new ConversionContextBuilder();
          b.setRateType(rateType);
          b.setProviderName(provider);
          return b.build();
      }
docs: Simple factory method for {@link ConversionContext}. For more
  possibilities to initialize a {@link ConversionContext}, please use a
  {@link javax.money.convert.ConversionContextBuilder},
  
  @param provider the provider name, not {@code null}
  @param rateType the required rate type.
  @return a new instance of {@link ConversionContext}