Fix dialyzer.

src/syn.erl

@@ -627,7 +627,7 @@ multi_call(Scope, GroupName, Message, Timeout) ->
 %% @doc Allows a group member to reply to a multi call.
 %%
 %% See {@link multi_call/4} for info.
--spec multi_call_reply({reference(), ClientPid :: pid()}, Reply :: term()) ->
+-spec multi_call_reply({ClientPid :: pid(), reference()}, Reply :: term()) ->
     {syn_multi_call_reply, reference(), Reply :: term()}.
 multi_call_reply(Caller, Reply) ->
     syn_pg:multi_call_reply(Caller, Reply).

src/syn_pg.erl

@@ -221,7 +221,7 @@ multi_call(Scope, GroupName, Message, Timeout) ->
     end, Members),
     collect_replies(orddict:from_list(Members)).
 
--spec multi_call_reply({reference(), ClientPid :: pid()}, Reply :: term()) ->
+-spec multi_call_reply({ClientPid :: pid(), reference()}, Reply :: term()) ->
     {syn_multi_call_reply, reference(), Reply :: term()}.
 multi_call_reply({CallerPid, Ref}, Reply) ->
     CallerPid ! {syn_multi_call_reply, Ref, Reply}.