@spec append_data(ProcessHub.Hub.t(), %{
  required(node()) => [
    {ProcessHub.child_spec(), pid(), ProcessHub.child_metadata()}
  ]
}) :: :ok

Appends remote data to the local process registry.

@spec broadcast_local_registry(ProcessHub.Hub.t(), [node()]) :: :ok

Broadcasts local registry data to the specified target nodes.

Called when new nodes join the cluster to share local process information.

@spec broadcastable_local_data(ProcessHub.Hub.t()) ::
  {:ok, [{ProcessHub.child_spec(), pid(), ProcessHub.child_metadata()}]}
  | :suppress

Returns {:ok, data} to broadcast, or :suppress.

A node that has hosted no local child since boot returns an empty local_sync_data/1; broadcasting it would make peers' detach_data/2 treat the node as authoritatively empty and wipe its records. We suppress that empty until the node has hosted a child at least once (latched in storage.misc, which resets on restart). A node that legitimately drained its children is already latched, so it still broadcasts its empty and peers reconcile.

@spec detach_data(ProcessHub.Hub.t(), %{
  required(node()) => [{ProcessHub.child_spec(), pid()}]
}) :: :ok

Detaches remote data from the local process registry.

@spec local_sync_data(ProcessHub.Hub.t()) :: [
  {ProcessHub.child_spec(), pid(), ProcessHub.child_metadata()}
]

Returns local node's process registry data used for synchronization.

Helper function to trigger interval synchronization.

The system will use the configured synchronization strategy.