typedef int(* libmem_driver_lock_fn_t)(libmem_driver_handle_t *h, uint8_t *start, size_t size)
  | A function pointer to a LIBMEM driver's lock function. Parameters:
  | h | A pointer to the handle of the LIBMEM driver.
  | start | A pointer to the initial memory address in memory range handled by driver to lock.
  | size | The number of bytes to lock.
Returns: The LIBMEM status result. The driver's lock function should lock size bytes of the memory range handled by the LIBMEM driver pointed to by start. If this operation is not required the function should return LIBMEM_STATUS_SUCCESS.