Subfetch

[jiftechnify]

Currently, it is inefficient to fetch events related to the events that are fetched in a streaming manner (via allEventsIterator etc.) using nostr-fetch because we must wait until all events are fetched and then query related events and we can't run these fetches concurrently.

Introducing the concept of "subfetch" may resolve this issue.

API sketch:
NostrFetcher.subfetch<T>(stream: AsyncIterable<T>, deriveFilters: (v: T) => Filter[]): AsyncIterable<NostrEvent>

where:

• stream is stream of things, usually NostrEvent but we have no reason to limit the type of items.
• deriveFilters is a function that derives Filters from each item from the stream.

Considerations:

• How to batch and merge filters?
• If we request events by ids, we don't have to wait responses from all relays.

[reyamir]

if we request events by ids, we still need to wait responses from all relays, because we can't sure that events present on certain relay or not