Behaviour for supervised content feeders (the put/share side).

put_content/2 is a plain blocking call — no addressable pid to cancel it from outside. This is the provider-side counterpart to macula_download: start_link/4,5 returns immediately with a pid, runs macula:put_content/2 in a linked worker, delivers the outcome to Module:handle_fed/2, and publishes sharing.put_started_v1 / sharing.put_completed_v1 mesh facts around the transfer — including outcome => cancelled if the feeder is stopped before the put resolves.

This is content sharing, not general-purpose RPC streaming — see macula_streamer / macula_stream_sink for that (streaming.* facts belong to that pair).

Example

   -module(doc_feeder).
   -behaviour(macula_feeder).
   -export([init/1, handle_fed/2]).
  
   init(Parent) -> {ok, Parent}.
  
   handle_fed(Result, Parent) ->
       Parent ! {fed, Result},
       {stop, normal, Parent}.

   {ok, Pid} = macula_feeder:start_link(doc_feeder, Pool, Realm,
       Bytes, self()).