Managed::merge API

[elramen]

Add Managed::merge(first: Managed<M>, second: Managed<N>) -> Managed<T>.

Then use this in the envelope function of the minidump and playstation endpoints instead of reject2 and accept. The idea is to use merge to do:

Managed<(DataCategory, usize)>, Managed<Item> -> Managed<(DataCategory, usize), Item>

and then map (without having to modify the records manually) to do:

Managed<(DataCategory, usize), Item> -> Managed<Box<Envelope>>

[linear-code]

RELAY-242

[pierceroberts]

Hello, I am looking to contribute.
Is this adding the merge function to relay-server/src/managed/managed.rs and updating the envelope functions in relay-server/src/endpoints/playstation.rs? In addition, will this be replacing both of the calls to reject2 & accept here:

 let event_id = common::event_id_from_items(&items)
        .reject2(&items, &managed_err)?
        .unwrap_or_else(EventId::new);
    let envelope = items.map(|items, records| {
        managed_err.accept(|_| ()); // There will be an envelope with (DataCategory::Error, 1) now
        records.modify_by(DataCategory::Error, 1);
        let envelope = Envelope::from_request(Some(event_id), meta)
            .with_items(items)
            .with_required_feature(Feature::PlaystationIngestion);
        Box::new(envelope)
    });

With the new merge function?
Thanks for the additional context.