Why not? I’m curious as to why it wouldn’t fit among those others. Not used broadly enough?

Given there's a focus on basic data structures it seems like a good fit.

Probably MQ as example for a message bus was not OSS and hip enough;)

kafka is a good fit when you design modern system. As your system grows larger, necessity of message queue becomes obvious. And kafka is probably the most widely used general-purpose high performance distributed q

check out distributed services in Go and you'll see why Kafka would be in this list.