static <T extends Response> RetryRuleWithContent<T> onException(Class<? extends Throwable> exception) {
        return onException(exception, Backoff.ofDefault());
    }
Returns a newly created a {@link RetryRuleWithContent} that will retry with
the {@linkplain Backoff#ofDefault() default backoff} if an {@link Exception} is raised and that is an
instance of the specified {@code exception}.
core/src/main/java/com/linecorp/armeria/client/retry/RetryRuleWithContent.java