Turns out this is just due to a very short MRT window in the KVUtils integration tests. (test start time + 1 second) is fine for a fast machine, but on a slow machine with a lot going on, it's too tight.

I've increased it to 10 seconds. I also refactored the way we compute them to make sure it's readable, because I find it difficult to figure out how long (1 followed by lots of zeroes) microseconds is in human-comprehensible time durations.

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