docs: public HttpConnection header(Map<String, List<String>> headerMap, boolean isOverride) {
  		if (MapUtil.isNotEmpty(headerMap)) {
  			String name;
  			for (Entry<String, List<String>> entry : headerMap.entrySet()) {
  				name = entry.getKey();
  				for (String value : entry.getValue()) {
  					this.header(name, StrUtil.nullToEmpty(value), isOverride);
  				}
  			}
  		}
  		return this;
  	}