That single threaded model has one major drawback — requests lose context: as they flow through multiple files and performs asynchronous operations, variables are not preserved throughout their life-cycle. Why is this painful? For example, often developers wish to include within each log entry a unique identifier so later one can correlate all the log entries of the same request — this is not very easy in 2018. 2019 brings new shiny new stuff and async-hooks is one of them (not entirely new but should get ou…