docs: public static String downloadString(String url, Charset customCharset, StreamProgress streamPress) {
  		if (StrUtil.isBlank(url)) {
  			throw new NullPointerException("[url] is null!");
  		}
  
  		FastByteArrayOutputStream out = new FastByteArrayOutputStream();
  		download(url, out, true, streamPress);
  		return null == customCharset ? out.toString() : out.toString(customCharset);
  	}