code: func BTCAddrBytesFromPubKeyBytes(pubKeyBytes []byte) (addrBytes []byte, checksum []byte) {
  	versionPrefix := btcPrefixPubKeyHash // TODO Make const or configurable
  	h160 := CalcHash160(pubKeyBytes)
  	_h160 := append([]byte{versionPrefix}, h160...)
  	checksum = CalcHash256(_h160)[:4]
  	return h160, checksum
  }
docs: // BTCAddrBytesFromPubKeyBytes returns a hex Bitcoin mainnet address and its checksum.