old := e.cached.Swap(newAcc)
			var a AccElem
			a.Size = atomic.LoadInt64(&old.Size)
			a.Total = atomic.LoadInt64(&old.Total)
			a.N = atomic.LoadInt64(&old.N)
			e.mu.Lock()
			e.lastMinuteLatency.addAll(t-1, a)
			e.mu.Unlock()
			acc = newAcc
		} else {
			// We may be able to grab the new accumulator by yielding.
			runtime.Gosched()
			acc = e.cached.Load()
		}
	}
	atomic.AddInt64(&acc.N, 1)