note that won't reset everything to 0, just force set every post which
has a count != 0
also this is kind of a bad way to do it. at least we stream objects, but
we could have it happen all inside our db with SELECT, DISTINCT and SUM,
i just don't know how to represent it in sea_orm. an intermediate
optimization may be selecting only certain columns but it's relevant
almost only for replies
no more "impl ..." hell, each trait has associated types so that we know
it's a "Self::Link" or a "Self::Actor", but in practice they can both be
a "serde_json::Value" and thus we can change its type. also Node::Array
is now a Vec<T> rather than Vec<Node<T>> because it makes more sense.
Node is Iterable and will yield zero (Empty|Link), one (Object) or many
(Array) Ts