HotStuff enables a correct leader to drive the protocol to consensus at the pace of actual (vs. maximum) network delay--a property called responsiveness--and with communication complexity that is linear in the number of replicas.
HotStuff is built around a novel framework that forms a bridge between classical BFT foundations and blockchains and allows the expression of other known protocols (DLS, PBFT, Tendermint, Casper), and ours, in a common framework.