NewLatency returns a new latency histogram with the given duration limit and with three significant figures of precision.

NewRotatingLatency returns a new rotating latency recorder with n buckets of history.

PublishLatency publishes rl as an expvar inside the global latency map (which is itself published under the key "latency").

Period is the size of a RotatingLatency bucket.

A Latency records information about the aggregate latency of an operation over time.

A RotatingLatency holds a rotating circular buffer of Latency objects, that rotates once per Period time.