@Override
        public String toString() {
            return MoreObjects.toStringHelper(this)
                              .add("nonBaseClientFactory", nonBaseClientFactory)
                              .add("cache", cache)
                              .toString();
        }
Returns a newly-created {@link Retrofit} based on the properties of this builder.
retrofit2/src/main/java/com/linecorp/armeria/client/retrofit2/ArmeriaRetrofitBuilder.java