How to set `listen.owner` and `listen.group` of php configuration file `www.conf` ?

I installed php on centos 7 ,

in php configuration file /etc/php-fpm.d/www.conf,

there are two items,they are listen.ownerand listen.group,how to set their values?

/etc/php-fpm.d/www.conf

//default values are  `apache`，I use nginx，so, I change them to `nginx`.
user = nginx   
group = nginx 



//default values are  `nobody`,how to set the values? `nginx` or `nobody` or `others`?
;listen.owner = nobody   
;listen.group = nobody

system has these users:

[root@demo ~]# cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-bus-proxy:x:999:998:systemd Bus Proxy:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:998:997:User for polkitd:/:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
chrony:x:997:995::/var/lib/chrony:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
nscd:x:28:28:NSCD Daemon:/:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
nginx:x:996:994:nginx user:/var/cache/nginx:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
mysql:x:995:993:MySQL server:/var/lib/mysql:/sbin/nologin