code: func CRCPolynomial(polynomial int64) FileStoreOption {
  	return func(o *FileStoreOptions) error {
  		if polynomial <= 0 || polynomial > int64(0xFFFFFFFF) {
  			return fmt.Errorf("crc polynomial should be between 1 and %v", int64(0xFFFFFFFF))
  		}
  		o.CRCPolynomial = polynomial
  		return nil
  	}
  }
docs: // CRCPolynomial is a FileStore option that defines the polynomial to use to create
  // the table used for CRC-32 Checksum.
  // See https://golang.org/pkg/hash/crc32/#MakeTable