看起来set headercurrentpage_start_time_x只被设置了一次，虽然它在循环中，但是headercurrentpage_start_time会被多次设置。下面是代码的片段，有没有人能给予我一些提示？提前感谢。

from("direct:api-query")
        .loopDoWhile(simple("${in.header.continue}"))
            .log(LoggingLevel.DEBUG," send to next page to \n -> {{project.query.url}}?limit={{project.query.limit}}&page=${in.header.currentPage}")
            .to("metrics:timer:simple.timer?action=start")
            // it will be set only once
            .setHeader("currentpage_start_time_x",simple(Long.valueOf(System.currentTimeMillis()).toString()))
            .process(
                    exg->{
                        LOG.info("currentpage_start_time_x->{}" , exg.getIn().getHeader("currentpage_start_time_x"));
                        //it will be set multiple times ( as same as loop size)
                        exg.getIn().setHeader("currentpage_start_time", System.currentTimeMillis());
                    }
            )