implement publishing using libp2p-js in browser without a pubsub provider

[estebanabaroa]

the browser should try to first publish p2p if it can, if it can't then it should try the pubsub providers. we need to test how fast/slow this is, if it's too slow, maybe we use the pubsub providers first, and then if they fail we fallback to p2p

[Rinse12]

Is the code for this feature ready?

[estebanabaroa]

I believe we can use this code to publish using libp2p gossipsub in the browser https://github.com/estebanabaroa/pubsub-test/blob/master/demo5.js

the only settings difference is we would use the default ipfs.io bootstrap nodes I think, or possibly our own nodes as bootstrap.

you first need to instantiate a libp2p instance like in the demo, then you pubsub.publish/subscribe, it's pretty easy

not sure how we would test the speed in production? maybe add some temporary experimental flag like PlebbitOptions.browserLibp2pJsPublish = true or something?