docs: public <T> Callable<T> asCallable(final Callable<T> callable) {
          return new Callable<T>() {
              public T call() throws Exception {
                  return ExtendedRetryTemplate.this.execute(new RetryCallback<T, Exception>() {
                      public T doWithRetry(RetryContext retryContext) throws Exception {
                          return callable.call();
                      }
                  });
              }
          };
      }