@Override
    public String toString() {
        StringBuilder strb = new StringBuilder(50);
        for (byte b : raw) {
            strb.append(" ").append(0xFF & (int) b);
        }
        return strb.toString().trim();
    }
Returns the raw byte array that constitutes this global id.
The returned value MUST NOT be modified.
document/src/main/java/com/yahoo/document/GlobalId.java