ByteVector put11(final int b1, final int b2) {
        int length = this.length;
        if (length + 2 > data.length) {
            enlarge(2);
        }
        byte[] data = this.data;
        data[length++] = (byte) b1;
        data[length++] = (byte) b2;
        this.length = length;
        return this;
    }