Jake C-T

`mux.Use(raven.Recovery)` looks to now be available as of https://github.com/getsentry/raven-go/pull/193

For "...`feeReceivers` to have a container class", consider using https://github.com/thehubbleproject/hubble-contracts/blob/master/ts/client/tokenbase.ts

Consider also crashing the node after n failed ETH provider re-connection attempts, or a duration of failed re-connections https://github.com/thehubbleproject/hubble-contracts/blob/master/ts/client/node.ts#L43-L45

FYI @ChihChengLiang @kautukkundan @jzaki

Consider using eslint, adding commit message linting rules.

Make linter follow these rules as makes sense https://github.com/ethereum/snake-charmers-tactical-manual/blob/master/style-guide.md

Update `prettier-plugin-solidity` as well.

Making a zero'd user state (`0, 0, 0, 0`) encode to `abi.encode(0)` appears to solve this issue https://github.com/thehubbleproject/hubble-contracts/pull/655/files#diff-f2cdceb56d3a8c8a457906a15fe58b0cdc283d6202375c7afeb61b2f485d6979 . However, a zero user state leaf is a valid state leaf....

Another thing to add, working on the test case for the non-existent `toIndex`. I think the initial `requires` in `Transition.sol.processSender` and `processReceiver` should to switch to become new `Result` enum...

From offline discussion of tradeoffs with @ChihChengLiang : If we use a special value for empty states (preimage), we will need to update all zero hashes and default state roots...