state machine

The retry loop's grown-up sibling. Retries protect one call; a breaker protects the whole dependency from a retry storm. The grade is in the half-open state, where letting through one probe instead of all of them is the difference between recovery and re-killing the server.

A stateful pass over sorted events, which most candidates get working in ten minutes. The reason it is asked is the next ten: in this domain a false positive is a person accused of something.