libspice-client-glib-2.0：The inputs handle ack function could not be called.

I use the libspice-client-glib-2.0 library with the following code:

gi.require_version('SpiceClientGLib', '2.0')
from gi.repository import SpiceClientGLib
...

Add g_message in each handle functions to verify that they were called correctly:

/* coroutine context */
static void inputs_handle_init(SpiceChannel *channel, SpiceMsgIn *in)
{
    g_message("in inputs_handle_init!");

    SpiceInputsChannelPrivate *c = SPICE_INPUTS_CHANNEL(channel)->priv;
    SpiceMsgInputsInit *init = spice_msg_in_parsed(in);

    c->modifiers = init->keyboard_modifiers;
}

/* coroutine context */
static void inputs_handle_modifiers(SpiceChannel *channel, SpiceMsgIn *in)
{
    g_message("in inputs_handle_modifiers!");
    
    SpiceInputsChannelPrivate *c = SPICE_INPUTS_CHANNEL(channel)->priv;
    SpiceMsgInputsKeyModifiers *modifiers = spice_msg_in_parsed(in);

    c->modifiers = modifiers->modifiers;
}

/* coroutine context */
static void inputs_handle_ack(SpiceChannel *channel, SpiceMsgIn *in)
{
    g_message("in inputs_handle_ack!");

    SpiceInputsChannelPrivate *c = SPICE_INPUTS_CHANNEL(channel)->priv;
    SpiceMsgOut *msg;

    c->motion_count -= SPICE_INPUT_MOTION_ACK_BUNCH;

    msg = mouse_motion(SPICE_INPUTS_CHANNEL(channel));
    if (msg) { /* if no motion, msg == NULL */
        spice_msg_out_send_internal(msg);
    }

    msg = mouse_position(SPICE_INPUTS_CHANNEL(channel));
    if (msg) {
        spice_msg_out_send_internal(msg);
    }

}

static void channel_set_handlers(SpiceChannelClass *klass)
{
    static const spice_msg_handler handlers[] = {
        [ SPICE_MSG_INPUTS_INIT ]              = inputs_handle_init,
        [ SPICE_MSG_INPUTS_KEY_MODIFIERS ]     = inputs_handle_modifiers,
        [ SPICE_MSG_INPUTS_MOUSE_MOTION_ACK ]  = inputs_handle_ack,
    };

    spice_channel_set_handlers(klass, handlers, G_N_ELEMENTS(handlers));
}

When using spicy as the client, all three functions print correctly, but when using libspice-client-glib-2.0, "in inputs_handle_ack!" of the third functions won't print properly.