Resolves the staker's EigenPod and encodes EigenPod.startCheckpoint(revertIfNoBalance).
Initiates an accounting checkpoint to update the pod's balance on-chain. Requires the staker to have a deployed EigenPod.

Nonce handling: The nonce is computed at call time. If you prepare multiple transactions before broadcasting, they will share the same nonce and only the first will succeed. Broadcast and confirm each transaction before preparing the next.