Add potential deprecation warning to Lwt_stream
Add potential deprecation warning to Lwt_stream

[skip ci]

c-cube/lwt,ocsigen/lwt,ocsigen/lwt,c-cube/lwt,ocsigen/lwt,rneswold/lwt,c-cube/lwt,rneswold/lwt,rneswold/lwt,rgrinberg/lwt,rgrinberg/lwt,rgrinberg/lwt,rgrinberg/lwt