code: public Request request() {
      if (!this.resolved) {
        throw new IllegalStateException("template has not been resolved.");
      }
      return Request.create(this.method, this.url(), this.headers(), this.requestBody());
    }
docs: Creates a {@link Request} from this template. The template must be resolved before calling this
  method, or an {@link IllegalStateException} will be thrown.
  
  @return a new Request instance.
  @throws IllegalStateException if this template has not been resolved.