public static String convertToUnhexExpression(byte[] bytes) {
        int len = bytes != null ? bytes.length : 0;
        if (len == 0) {
            return EMPTY_STRING_EXPR;
        }

        int offset = UNHEX_PREFIX.length;
        byte[] hexChars = new byte[len * 2 + offset + UNHEX_SUFFIX.length];
        System.arraycopy(UNHEX_PREFIX, 0, hexChars, 0, offset);
        System.arraycopy(UNHEX_SUFFIX, 0, hexChars, hexChars.length - UNHEX_SUFFIX.length, UNHEX_SUFFIX.length);
        for (int i = 0; i < len; i++) {
            int v = bytes[i] & 0xFF;
            hexChars[offset++] = HEX_ARRAY[v >>> 4];
            hexChars[offset++] = HEX_ARRAY[v & 0x0F];
        }
        return new String(hexChars, StandardCharsets.UTF_8);
    }
Converts given byte array to unhex() expression.

@param bytes byte array
@return non-null expression
clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseValues.java