Are there any really performant #nostr relay implementations that are still being developed? 

I’m expecting thousands or even tens of thousands of simultaneous connections. And I really need NIP-42. 

Strfry hasn’t been updated in 5 months. And it doesn’t support NIP-42. 

Nostream is definitely popular, but I worry about the performance. And it doesn’t support NIP-42 either. 

Maybe nostr-rs-relay?

#asknostr