title: Webflux thread mode for IO bound web application
body: <p>I got set up a webflux based application that essentially needs to serialize some entity read from a newo4j datasource in reactive way in streaming mode (new JSON line per object). We're talinkg about IO bound processes, with almost no CPU ops involved (aside from serializing a flat entity to DTO and DTO to json).
  What we're experiencing is what we know: we've been capped by the numer of cores, so we got just 4 different threads that serialize the data.
  But can we move the serialization phase on other threads? Since the process is IO bound, with a level of concurrency &gt; 4, we wait the first reactor-epoll-thread to be free, while actually we could already make the query and mapping the result.
  Can we move the serialization part as streaming mode to some thread else?</p>
  <p>Thanks,
  FB</p>