func math.Log2

3 uses

	math (current package)
		log10.go#L17: func Log2(x float64) float64

	math/big
		natconv.go#L276: 	i := int(float64(x.bitLen())/math.Log2(float64(base))) + 1 // off by 1 at most

	github.com/aws/aws-sdk-go/aws/client
		default_retryer.go#L113: 	actualRetryCount := int(math.Log2(float64(minDelay))) + 1