WIP
Chain Reorganisation
https://github.com/ethereum/go-ethereum/blob/de39513ced05f120b30b0daa49003982cc6b2426/miner/worker.go#L57
code: geth
// miningLogAtDepth is the number of confirmations before logging successful mining.
miningLogAtDepth = 7
https://medium.com/@alpalpalp/chain-splits-and-resolutions-d3398bddf4ab
https://blog.zeppelin.solutions/designing-the-architecture-for-your-ethereum-application-9cec086f8317
https://blog.ethereum.org/2015/08/08/chain-reorganisation-depth-expectations/