code: func MinimumShiftFor(max int64, depth uint32) (uint32, bool) {
  	for shift := uint32(0); shift < 32; shift++ {
  		if validIndexPos(int(max), shift, depth) {
  			return shift, true
  		}
  	}
  	return 0, false
  }
docs: // MinimumShiftFor returns the lowest minimum shift value that can be used to index
  // the given maximum position with the given index depth.