docs: public void printInterceptorChain(InterceptorChain chain) {
          Iterator<Interceptor<? extends Message>> it = chain.iterator();
          String phase = "";
          StringBuilder builder = null;
          while (it.hasNext()) {
              Interceptor<? extends Message> interceptor = it.next();
              if (interceptor instanceof DemoInterceptor) {
                  continue;
              }
              if (interceptor instanceof PhaseInterceptor) {
                  PhaseInterceptor pi = (PhaseInterceptor)interceptor;
                  if (!phase.equals(pi.getPhase())) {
                      if (builder != null) {
                          System.out.println(builder.toString());
                      } else {
                          builder = new StringBuilder(100);
                      }
                      builder.setLength(0);
                      builder.append("             ");
                      builder.append(pi.getPhase());
                      builder.append(": ");
                      phase = pi.getPhase();
                  }
                  String id = pi.getId();
                  int idx = id.lastIndexOf('.');
                  if (idx != -1) {
                      id = id.substring(idx + 1);
                  }
                  builder.append(id);
                  builder.append(' ');
              }
          }
  
      }