如何持久化Erlang程序初始化中的变量，以便在其他函数中使用？

start() ->
    InitialState = #{var => initial_value},
    spawn(fun() -> loop(InitialState) end).

loop(State) ->
    receive
        {set_var, NewValue} ->
            NewState = maps:update(var, NewValue, State),
            loop(NewState);
        {get_var, Pid} ->
            Pid ! {var, maps:get(var, State)},
            loop(State);
        stop ->
            ok
    end.

set_var(Pid, NewValue) ->
    Pid ! {set_var, NewValue}.

get_var(Pid) ->
    Pid ! {get_var, self()},
    receive
        {var, Value} -> Value
    end.