anchor.diff:      lager:info("~p: node ~p received forwarded write for key ~p with value ~p", [?MODULE, node(), Key, Value]),
   
       %% Send backup message to backups.
  -    lists:foreach(fun(Backup) -> forward_message(Backup, {backup, From, Key, Value}) end, Backups),
  +    lists:foreach(fun(Backup) -> psend(Backup, {backup, From, Key, Value}) end, Backups),
   
       %% Send the response to the caller.
       gen_server:reply(From, ok),
  
positive.code:     lager:info("~p: node ~p received forwarded read for key ~p and returning value ~p", [?MODULE, node(), Key, Value]),
  
      %% Send the response to the caller.
      gen_server:reply(From, {ok, Value}),
  
      %% No need to send acknowledgement back to the forwarder: 
      %%  - not needed for control flow.
  
negative.code:             Store = write(Key, Value, Store0),
  
              %% Forward to collaboration message.
              Myself = pnode(),
              psend(Collaborator, {collaborate, From, Myself, Key, Value}),
              lager:info("~p: node ~p sent replication request for key ~p with value ~p", [?MODULE, node(), Key, Value]),
  
              %% Wait for collaboration ack before proceeding for n-host resilience (n = 2).
  