Method segmentation

src/main/java/top/misec/push/AbstractPush.java:140–142

消息分割 对于一条消息可能太长，需要分割按顺序发送 @param pushBody 消息内容 @return 分割结果，默认不分割

(PushMetaInfo metaInfo, String pushBody)

     * @return 分割结果，默认不分割
     */
    protected List<String> segmentation(PushMetaInfo metaInfo, String pushBody) {
        return Collections.singletonList(pushBody);
    }

    @Override
    public <V> void onRetry(Attempt<V> attempt) {