@Override
    public Feign.Builder options(final Request.Options options) {
      throw new UnsupportedOperationException(
          "Options should be provided directly during construction of Vertx WebClient.");
    }
Defines target and builds client.

@param target target instance
@param <T> class of API interface
@return built client
vertx/feign-vertx/src/main/java/feign/VertxFeign.java