title: Spring Boot BufferedApplicationStartup drained after first request
body: <p>I am using the great new <a href="https://docs.spring.io/spring-framework/docs/5.3.x/reference/html/core.html#context-functionality-startup" rel="nofollow noreferrer">ApplicationStartup recording feature</a> of Spring 5.3 / Spring Boot 2.4, with <a href="https://docs.spring.io/spring-boot/docs/2.4.0/api/org/springframework/boot/context/metrics/buffering/BufferingApplicationStartup.html" rel="nofollow noreferrer">BufferedApplicationStartup</a> (only provided by SB 2.4).</p>
  <p>However,</p>
  <ul>
  <li>on the very first access to the /startup endpoint I seem to get all startup events, but</li>
  <li>on subsequent calls to the endpoint I only get 3 (exactly 3) new events.</li>
  </ul>
  <p>Is this documented somewhere? Is it configurable? It would be great if the data was not lost after the first call. Or is it a bug?</p>