Block processor could query notes and swaps in parallel instead of in sequence

[turbocrime]

prax/packages/query/src/block-processor.ts

Lines 501 to 510 in 7bcf54d

	for (const nullifier of nullifiers) {
	const readPromise = (async () => {
	const record =
	(await this.indexedDb.getSpendableNoteByNullifier(nullifier)) ??
	(await this.indexedDb.getSwapByNullifier(nullifier));
	return { nullifier, record };
	})();
	readOperations.push(readPromise);
	}

This nullish coalescing operator will wait for getSpendableNoteByNullifier to complete before attempting getSwapByNullifier.

Potentially, these promises could be raced to completion, possibly leading to benefit if the nullifier represents a swap. An index by nullifier is present, so this may not be a significant benefit.

Difficulty: An absent item will return with 'undefined', preventing the simplest Promise.race technique.