These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.02 s (backtrack: 0/20).

[ebuild  N     ] acct-group/turnserver-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/turnserver-0-r3::gentoo  0 KiB
[ebuild  N     ] net-im/coturn-4.17.2::gentoo  USE="sqlite -mongodb -mysql -postgres -redis" 794 KiB

Total: 3 packages (3 new), Size of downloads: 794 KiB