Failure impact

Failures will lead to timeouts, which in turn could lead to failed requests (this is a bug if failure enters in Garage tolerance) and to increased latency as some retries might be performed.

How we proceed: we pause (kill -STOP xxx) one Garage process. The idea is we don't want to close the TCP connection that would signal too easily that a crash occured. Instead, we want to simulate a network error or an overloaded process, ie. a 'non-collaborating' crash.