code: func findMSB(value uint64) int {
  	for i := bitsInUint64 - 1; i >= 0; i-- {
  		if value&(1<<uint(i)) != 0 {
  			return int(i)
  		}
  	}
  	return -1
  }
docs: // return the bit position of the most significant bit of the number passed in (base zero)