From what I see in the function handleIhave in gossipsub.go
https://github.com/libp2p/go-libp2p-pubsub/blob/master/gossipsub.go#L757

The logic is that when you receive IHAVE, you check if you have seen the message already or not. If not, just send IWANT right away.

This makes it possible that you will send many IWANTs for a single message which results to receiving many copies of the message.

AFAIU currently rust-libp2p sends only one IWANT per message so that it doesn't receive too many copies. Should go-libp2p-pubsub do the same?