feat: remove MPLEX by default

[Jorropo]

Mplex does not implement backpressure, our implementation will randomly reset streams if buffers overflow instead of risking deadlocks.

In the past we had a bug where kubo nodes would prefer mplex over yamux. Turning off mplex make our connections to thoses nodes negociate yamux.

[Jorropo]

cc @marten-seemann @mxinden @achingbrain

[aschmahmann]

@ianopolous I recall you recently asked about mplex in jvm-libp2p. Not sure if this will effect you.

[ianopolous]

Thanks for the pointer @aschmahmann . Yes jvm-libp2p currently only has the mplex muxer and no yamux or quic. So disabling mplex would partition all those nodes from the network.

[Jorropo]

@ianopolous that a blocker, thx for speaking up, do you have plans to add yamux at some point in the future ? I guess you must be running in the same stream resets issues we were seeing in the past.

[achingbrain]

js-ipfs doesn't ship with yamux by default, though it can be used via custom config. There should probably be a release with it included, if mplex is being removed from kubo.

[Jorropo]

I'll not do this now, this PR was a beacon for "do people complain if we drop this broken protocol ?" answer is yes 🙏.

We will revisit this in the future (1y ?), please consider adding support for the not broken muxer (yamux) in your implementations. ^^

[ianopolous]

@Jorropo Yep I'll prioritise adding yamux support now.

[Jorropo]

@ianopolous I'm not asking to prioritize anything, feel free to do it if you want, but if you don't it's fine, we can keep mplex in Kubo.

The main goals are:

1. Avoid divergent defaults between Kubo and go-libp2p. (go-libp2p does not have mplex by default anymore)
2. Better auto negotiation with buggy Kubo nodes that prioritize mplex over yamux.

Neither are urgent or even real problems right now, the point I was trying to make is that if mplex is completely useless might as well remove it as this have slight positive benefits, turns out, it is still usefull so we can keep it.

[ianopolous]

@Jorropo FYI, we've implemented yamux now.

[lidel]

Continued in ipfs/js-ipfs#4318 (js-ipfs needs to support both, so when we remove mplex from kubo in the future, it wont break)