title: How to get event after network IO transfer is complete in spring webflux
body: <p>I am using spring webflux in my application. In an application I want to cache some binaries and when requested by the client return cached binaries.</p>
  <p>Sometimes the binary size is large (Around 200 Mb) so after return, it takes some time to send to the network depending upon network bandwidth. So I want some control over network IO transfer, I wanted to perform some activity after network transfer is complete.
  Can we get some handler\event in spring webflux which gets triggered after network transfer is done?</p>