Comment by rwmj

My colleague added MSG_MORE support throughout libnbd[1]. It proved quite an elegant way to solve a common problem: You want to assemble a message in whatever protocol you're using, but it's probably being assembled across many functions (or in the case of libnbd, states in a complicated state machine), and using expanding buffers or whatever is a pain. So instead we let the kernel assemble it, or allow the kernel to make the decision to group the data or send it. The down side is multiple socket calls, but combining it with io_uring is a possibility to avoid this.

[1] https://gitlab.com/search?search=MSG_MORE&nav_source=navbar&...