message: Document recent feature addition
diff: @@ -9,14 +9,16 @@ is based on [Keep a Changelog](https://keepachangelog.com).
  - The new classes `json_value`, `json_array` and `json_object` allow working
  with JSON inputs directly. Actors can also pass around JSON values safely.
  -- Fused stages now properly forward errors during the initial subscription to
  - their observer.
  +- Futures can now convert to observable values for making it easier to process
  + asynchronous results with data flows.
  ### Fixed
  - The SPSC buffer now makes sure that subscribers get informed of a producer has
  already left before the subscriber appeared and vice versa. This fixes a race
  on the buffer that could cause indefinite hanging of an application.
  +- Fused stages now properly forward errors during the initial subscription to
  + their observer.
  ## [0.19.0-rc.1] - 2022-10-31
  