Comment by scharman

I believe it just emits at least one packet on each system 'write' call. As long as your 'write' invocations are larger blocks then I'd expect you'd see very little difference with O_NDELAY enabled or disabled. I've always assumed you want to limit system calls so I'd always assumed it to be better practice to encode to a buffer and invoke 'write' on larger blocks. So this feels like a combination of issues.

Regardless, overriding a socket parameter like this should be well documented by Golang if that's the desired intent.