v1 state

greeter

Instance

Instance exposes the singleton so a test (or a rollback) can re-register it without redeploying.

init.2

Register

Register re-registers this implementation with the facade. init does it once at deploy; exposing it as a transaction is what makes a rollback to an already-deployed version a single call.

Seal

Seal asks the facade to end its upgradeability, forever. It only succeeds while this implementation is the live one: the facade reads the caller off the crossing frame, so this cannot be used to seal somebody else's tenure.