Function join_svs_group 

pub fn join_svs_group(
    group: Name,
    local_name: Name,
    send: Sender<Bytes>,
    recv: Receiver<Bytes>,
    config: SvsConfig,
) -> SyncHandle

Join an SVS sync group.

Spawns a background task that:

1. Periodically sends Sync Interests with the local state vector
2. Processes incoming Sync Interests, merging their state vectors
3. Emits SyncUpdate for any detected gaps (new data to fetch)

The returned SyncHandle provides recv() for updates, publish() to announce new local data, and publish_with_mapping() to include mapping metadata for fast consumer fetching.

Arguments

• group — sync group prefix (e.g. /ndn/svs/chat)
• local_name — this node’s name within the group
• send — channel to send outgoing packets (Interests)
• recv — channel to receive incoming packets (Interests from peers)
• config — SVS configuration