code: public static <T> T buildProxy(String proxyType, Class<T> clazz, Invoker proxyInvoker) throws Exception {
          try {
              ExtensionClass<Proxy> ext = ExtensionLoaderFactory.getExtensionLoader(Proxy.class)
                  .getExtensionClass(proxyType);
              if (ext == null) {
                  throw ExceptionUtils.buildRuntime("consumer.proxy", proxyType,
                      "Unsupported proxy of client!");
              }
              Proxy proxy = ext.getExtInstance();
              return proxy.getProxy(clazz, proxyInvoker);
          } catch (SofaRpcRuntimeException e) {
              throw e;
          } catch (Throwable e) {
              throw new SofaRpcRuntimeException(e.getMessage(), e);
          }
      }
docs: 构建代理类实例
  
  @param proxyType    代理类型
  @param clazz        原始类
  @param proxyInvoker 代码执行的Invoker
  @param <T>          类型
  @return 代理类实例
  @throws Exception