What is SeqWrap for?

[KyleMaas]

I have yet to see a Margaret query in go-ssb that doesn't use SeqWrap. What is the purpose of it, and why isn't it the default (or only option) if that's the way it's always used?

[decentral1se]

@KyleMaas afaiu when querying the log, instead of having to first get back a list of sequence numbers and then query the log again to pull out the items, Seqwrap brings back both the sequence number and item in one query?

margaret/qry.go

Lines 29 to 31 in 4f58150

	// SeqWrap makes the source return values that contain both the item and its
	// sequence number, instead of the item alone.
	SeqWrap(bool) error

[KyleMaas]

@decentral1se

Is there a situation where you would not want this behavior? I don't think I've seen anything that doesn't use this.

[decentral1se]

@KyleMaas I'm not sure but I guess we could imagine a scenario where only grabbing the sequence number is less overhead for the query caller. Are you looking to remap this API surface or? Definitely wanna find time to do a docs sprint here...

[KyleMaas]

@decentral1se

I've spotted several opportunities for race conditions which can corrupt things when SeqWrap is used. Just trying to understand it better.