Reactive

Back-pressure is an important feedback mechanism that allows systems to gracefully respond to load rather than collapse under it. The back-pressure may cascade all the way up to the user, at which point responsiveness may degrade, but this mechanism will ensure that the system is resilient under load.

An important aspect of reactive approach to concurrent programming is non-blocking processing. This post compares blocking vs non-blocking processing in general terms to highlight reactive idea in a nutshell.