[3/4] - lnwallet/chancloser: add new protofsm based RBF chan closer (channel closing)

https://github.com/lightningnetwork/lnd/pull/8512

Host: ProofOfKeags  -  PR author: roasbeef

Questions

  • When considering the existing coop-close protocol, who pays the closing fees?
  • ⁠What are some of the failure modes that can arise from fee negotiation?
  • ⁠What are the incentives for the the following party/scenario: initiator/initiator closes, target/initiator closes, initiator/target closes, target/target closes?
  • ⁠Ideally who should pay the fees during a coop close and why?
  • In coop close v2 who pays the coop close fees?
  • ⁠What are the different intermediate states a closing negotiation can be in?
  • ⁠How can we use this new protocol state machine to do fee bumping?
  • ⁠Which party can fee bump the closing transaction?
  • ⁠What are some practical benefits of RBF’ing a coop close transaction?
  • ⁠SWE: What does the new protofsm library do?
  • ⁠SWE: What are some advantages of using protofsm here?
  • ⁠SWE: What are some potential drawbacks of using protofsm here?