title: Webflux drops when overflow strategy is buffer
body: <p>When I call <code>subscribe()</code> calls outside the reactive chain. Does it not follow the spring webflux's overflow strategy?</p>
  <pre class="lang-kotlin prettyprint-override"><code>fooRepository.findOne()
      .doOnNext { barRepository.save(bar).subscribe() }
      .flatMap { ... }
  </code></pre>
  <p>I have this strange behavior which <code>barRepository.save</code> sometimes works and sometimes not with no error. I think it is being dropped.</p>
  <p>When server is busy, can subscribe() calls inside doOnNext be dropped?</p>
  <p><a href="https://www.e4developer.com/2018/04/28/springs-webflux-reactor-parallelism-and-backpressure/" rel="nofollow noreferrer">This post</a> says default overflow strategy is BUFFER.</p>
  <p>Does subscribe() calls inside doOnNext has different strategy?</p>