EXPORTED void mailbox_set_wait_cb(void (*cb)(void *), void *rock)
{
    mailbox_wait_cb = cb;
    mailbox_wait_cb_rock = rock;
}
EXPORTED void mailbox_set_wait_cb(void (*cb)(void *), void *rock)
{
    mailbox_wait_cb = cb;
    mailbox_wait_cb_rock = rock;
}