another nice thing is that this format ensures the id is at the start, meaning its very easy to reject parsing/verifying the entire thing when when checking if you already have it:

for field in packed_note {

// first field peeked when looking at the bytes

if let ParsedField::Id(id) = field {

if cache.contains(id) {

break;

}

}

}

I had to really hack this in my json parser on nostrdb to get this working