code: func (f *freeClientPool) calcLogUsage(e *freeClientPoolEntry, now mclock.AbsTime) {
  	dt := e.linUsage + int64(now)
  	if dt < 1 {
  		dt = 1
  	}
  	e.logUsage = int64(math.Log(float64(dt))*fixedPointMultiplier) + f.logOffset(now)
  }
docs: // calcLogUsage converts recent usage from linear to logarithmic representation
  // when disconnecting a peer or closing the client pool