On macOS, that is. The goals are largely for testing, where we'd like to know the maximum and minimum memory our processes are using, but we'd also like to know it on crash.
Our current method is to use ps periodically and grab the appropriate field, but is there a better way? (I looked at MetricKit, but it's not as useful on macOS; I filed FB13640765 "MetricKit would be awesome with more mac features" a couple of months ago.)