TransferPrepare

The encoded TransferTicket. Opaque; the client is a courier.

Where the target is.

Which shard, so the client can say which one it reached.

What the target is running. The client checks this before it connects — arriving with the wrong content is a handshake rejection, and finding that out here costs nothing.

The target's tick estimate, so the client can pre-sync during the overlap rather than resync after the switch.

What the source realm tells the client so it can open its second session.