@Override
    public final void writeRaw(char ch) {
        if (ch > 128) {
            throw new JSONException("not support " + ch);
        }

        if (off == bytes.length) {
            grow0(off + 1);
        }
        bytes[off++] = (byte) ch;
    }
A faster alternative that is functionally equivalent to Long.expand(i, 0x0F0F_0F0F_0F0F_0F0FL)
core/src/main/java/com/alibaba/fastjson2/JSONWriterUTF8.java