void psi_let_callback_free(struct psi_let_callback **cb_ptr);
void psi_let_callback_dump(int fd, struct psi_let_callback *cb, unsigned level);
void psi_let_callback_free(struct psi_let_callback **cb_ptr);
void psi_let_callback_dump(int fd, struct psi_let_callback *cb, unsigned level);