int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *mapped, size_t *allocated);
void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t mapped, size_t allocated);
int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *mapped, size_t *allocated);
void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t mapped, size_t allocated);