ZPOOL_HIST_WHO
if (nvlist_exists(rec, ZPOOL_HIST_WHO)) {
uid_t who = fnvlist_lookup_uint64(rec, ZPOOL_HIST_WHO);
if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_WHO, &uint64) == 0)
fnvlist_add_uint64(nvarg, ZPOOL_HIST_WHO, crgetruid(CRED()));