return null from Rate#msPerEvent if it's been less
than warmupMs since construction or Rate#clear.
Readonlyperiodthe length of time to retain event timestamps for computing rate. Events older than this value will be discarded.
Readonlywarmupreturn null from Rate#msPerEvent if it's been less
than warmupMs since construction or Rate#clear.
the length of time to retain event timestamps for computing rate. Events older than this value will be discarded.