https://en.wikipedia.org/wiki/Vector_clock
https://blog.cosmos.network/consensus-compare-casper-vs-tendermint-6df154ad56ae#215d
https://blog.cosmos.network/light-clients-in-tendermint-consensus-1237cfbda104
http://scattered-thoughts.net/blog/2012/08/16/causal-ordering/
https://github.com/ethereum/wiki/wiki/RLP
https://developers.google.com/protocol-buffers/
https://github.com/tendermint/go-amino
https://developers.google.com/protocol-buffers/docs/proto3