Buffering issues with nginx

[Dan34]

In nginx docs I see sndbuf option in listen directive.
Is there something that I don't understand about it, or developers of nginx
don't understand meaning of sndbuf... but I do not see a point to set sndbuf
on a listening socket. It just does not make any sense!
sndbuf/rcvbuf is needed perhaps for an upstream proxy connection, or for a
connected socket (from outside), but it just have no meaning to set that on
a listening socket. Total nonsense.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,275526,275730#msg-275730