public int length() {
		return (this.appendable != null ? this.appendable.toString().length() + StrUtil.length(suffix) :
				null == this.emptyResult ? -1 : emptyResult.length());
	}
@Test
	public void lengthTest(){
		StrJoiner joiner = StrJoiner.of(",", "[", "]");
		assertEquals(joiner.toString().length(), joiner.length());

		joiner.append("123");
		assertEquals(joiner.toString().length(), joiner.length());
	}