Send direct message or request to a peer using gossip

Using rust-libp2p is it possible to send direct message (without awaiting a reply) or a request (with reply) to a peer by its ID using gossip?

Or it’s only viable via streams? In that case what if peer is unreachable by the node? Will other peers propagate it somehow to destination peer?

In my pet project I have a stable leader which broadcasts to peers and awaiting responses from them, other peers do not have to see their peers responses, what is the proper way to implement such behaviour?

Hello! That’s an interesting question. I think the correct behavior is to use the gossip sub for broadcast but if you want to do a direct interaction with another peer you should use the request-response protocol.

Perhaps there is anything to avoid request/response? I do not want peer to ack message, the response in that case is an overkill.