Function deltachat::receive_imf::add_or_lookup_contacts_by_address_list

async fn add_or_lookup_contacts_by_address_list(
    context: &Context,
    address_list: &[SingleInfo],
    origin: Origin
) -> Result<Vec<ContactId>>

Looks up contact IDs from the database given the list of recipients.

Returns vector of IDs guaranteed to be unique.