public static CharSequence escapeCsv(CharSequence value) {
        return escapeCsv(value, false);
    }
@Test
    public void escapeCsvGarbageFree() {
        // 'StringUtil#escapeCsv()' should return same string object if string didn't changing.
        assertSame("1", StringUtil.escapeCsv("1", true));
        assertSame(" 123 ", StringUtil.escapeCsv(" 123 ", false));
        assertSame("\" 123 \"", StringUtil.escapeCsv("\" 123 \"", true));
        assertSame("\"\"", StringUtil.escapeCsv("\"\"", true));
        assertSame("123 \"\"", StringUtil.escapeCsv("123 \"\"", true));
        assertSame("123\"\"321", StringUtil.escapeCsv("123\"\"321", true));
        assertSame("\"123\"\"321\"", StringUtil.escapeCsv("\"123\"\"321\"", true));
    }