with gossipsub subscribers may not receive the first couple of messages

Nobody has claimed this yet.

While trying to sync js repos with go-ipfs 0.5.x i notice pubsub tests were failing for js-ipfs-http-client the specific test works like this:

1. peer1 swarm connects to peer2
2. peer1 and peer2 subscribe to topicA
3. peer2 runs ipfs.pubsub.peers() multiple times until it sees peer1
4. peer2 publishes a msg to the topic
5. test asserts that both peers receive the msg

So this test started to fail with go-ipfs 0.5 talking to @aschmahmann we discovered that this behaviour is due to 0.5 defaulting to gossipsub because with floodsub the test passes.

To make the test pass with gossipsub i needed to add a ~2s (may work with less just a random number) delay between step 3 and 4.

Can we remove the need for that delay and make gossipsub work like floodsub ?

issue https://github.com/ipfs/js-ipfs/issues/3030
pr https://github.com/ipfs/js-ipfs/pull/3013

Start by reproducing the described pubsub test flow with go-ipfs 0.5.x, comparing gossipsub and floodsub behavior around ipfs.pubsub.peers(). Trace the subscription and peer-discovery path before the publish step; done means both peers receive the first message without an arbitrary delay.

Written by the indexing model from the issue text.