PutObjectRequest request = new PutObjectRequest(bucket, key, srcPath);

JObject o = new JObject();
// 不返回原图
o["is_pic_info"] = 1;
JArray rules = new JArray();
JObject rule = new JObject();
rule["bucket"] = bucket;
rule["fileid"] = "qrcode.jpg";
//处理参数，规则参见：https://www.tencentcloud.com/document/product/436/54070?from_cn_redirect=1
rule["rule"] = "QRcode/cover/<mode>";
rules.Add(rule);
o["rules"] = rules;

string ruleString = o.ToString(Formatting.None);
request.SetRequestHeader("Pic-Operations", ruleString);
//执行请求
PutObjectResult result = cosXml.PutObject(request);

//二维码覆盖功能，将对识别出的二维码覆盖上马赛克。取值为0或1。0表示不开启二维码覆盖，1表示开启二维码覆盖，默认值0
QRCodeRecognitionRequest request = new QRCodeRecognitionRequest(bucket, key, 0);

QRCodeRecognitionResult result = cosXml.QRCodeRecognition(request);