typedef int(* libmem_driver_fill_fn_t)(libmem_driver_handle_t *h, uint8_t *dest, uint8_t c, size_t size)
  | A function pointer to a LIBMEM driver's fill function. Parameters:
  | h | A pointer to the handle of the LIBMEM driver.
  | dest | A pointer to the memory address in memory range handled by driver to write data to.
  | c | The data byte to write.
  | size | The number of bytes to write.
Returns: The LIBMEM status result. The driver's fill function writes size bytes of value `to` the memory address handled by the LIBMEM driver pointed to by dest. If this operation is not required the function should return LIBMEM_STATUS_SUCCESS.