Use F3 Finalized in more parts of the system

[tediou5]

Now that we have F3, we can finalize much faster.
But many parts of the system are still using EC ChainFinality, for example, when fetching randomness.

Also, for snapshots, is it possible to reduce it to 900 epochs (for reporting on consensus faults) + F3 Finalized(or fall back to EC Finality)?

[masih]

• Start here. The work is well on the way to deeply integrate F3 with what finality means across Lotus APIs. The master branch of Lotus already does this for the v2 APIs documented in that document, and is planned to be released shortly after the F3 activation.
• Watch my talk titled "F3 Aware Lotus APIs and what it means for you", scheduled for today at FDS virtual event Tools & Builders track for a presentation on the new APIs that do this. See schedule here
• The combination of a simple v2 ChainGetTipSet and existing v1 APIs should offer you everything that you need in terms of taking advantage of fast finality until v2 APIs are expanded/matured to fully deprecate v1/v0 APIs.
• Ask away on any questions that you may have. Feedback is most welcome. It's the early days of the v2 experimental APIs and we are keen to get as much feedback as possible before making the v2 APIs too verbose.

[masih]

Also, for snapshots, is it possible to reduce it to 900 epochs (for reporting on consensus faults) + F3 Finalized(or fall back to EC Finality)?

This is possible but requires further adjustments in the protocol since the 900 epoch EC finality is still required for reporting consensus fault. See slack discussion for further context.