code: private Response make() throws IOException {
          synchronized (this.lock) {
              if (this.transformed.isEmpty()) {
                  this.transformed.add(
                      new RsWithBody(
                          this.origin,
                          RsPrettyXml.transform(this.origin.body())
                      )
                  );
              }
          }
          return this.transformed.get(0);
      }
docs: Make a response.
  @return Response just made
  @throws IOException If fails