public CidrBlock addByte(int byteOffset, int n) {
        int oldByte = getByte(byteOffset);
        int newByte = 0xFF & (oldByte + n);
        return addByteRaw(byteOffset, newByte - oldByte);
    }
Add 'n' to the byte at the given offset, truncating overflow bits.  0 refers to the most significant byte of the address.
vespajlib/src/main/java/ai/vespa/net/CidrBlock.java