zap_add
zap_add(zap, ti, sizeof(sa_attr_type_t), sacnt,
zap_add(zap, name, sizeof(uint64_t), 1, (uint8_t *)&val);
zap_add(zap, name, sizeof(uint64_t), 1, (uint8_t *)&val);
zap_add(zap, name, 1, strlen(val) + 1, (const uint8_t *)val);
void zap_add(zfs_zap_t *, const char *, size_t, size_t, const uint8_t *);