Adding Negentropy support

[pippellia-btc]

https://github.com/nostr-protocol/nips/blob/master/77.md

[nogringo]

Do you have an idea of when this will be implemented ?

[pippellia-btc]

Not really. I don't want to promise a date because at the moment I am busy with other things.

Ideally someone builds a good negentropy library that I can integrate easily into rely. And no, not https://github.com/HORNET-Storage/go-negentropy as that is riddled with bugs like this one in types.go line 135

func (acc *Accumulator) Negate() {
	for i := range acc.Buf {
		acc.Buf[i] = ^acc.Buf[i]
	}

	var one []byte
	one[0] = 1 // Assuming little-endian; if big-endian, use one[len(one)-1] = 1

	acc.AddBytes(one)
}