Notes on changing SLOT_DURATION

[seunlanlege]

Hyperbridge nexus currently uses a slot duration of 12 seconds on mainnet. If for whatever reason, this needs to change, whether to support elastic scaling. It's important that connected chains do not learn of an incorrect state commitment timestamp, more critically a timestamp that is incorrectly greater than hyperbridge's timestamp as this enables timeouts for arbitrary requests, even delivered ones.

So updating the SLOT_DURATION requires some coordinated effort. Solochains and parachains must disconnect from hyperbridge before it performs it's slot duration change. Only reconnecting with the updated slot duration after the change is completed. Evm chains must be configured with a new consensus client ahead of the change, so they never calculate the incorrect timestamp