add WatchParameter and example

Signed-off-by: chuxuezhe11 <hanjixiao@huawei.com>

bin/example/bytrace_example.cpp

@@ -0,0 +1,76 @@
+#include <cstring>
+#include <unistd.h>
+#include <iostream>
+#include <thread>
+#include "bytrace.h"
+
+using namespace std;
+constexpr uint64_t label = BYTRACE_TAG_OHOS;
+
+void func1()
+{
+    cout << "func 1" << endl;
+    sleep(1);
+}
+
+void func2()
+{
+    cout << "func 2" << endl;
+    sleep(2);
+}
+
+void func3()
+{
+    cout << "func 3" << endl;
+    int num = 0;
+    for(int i=0; i < 5; i++) {
+        CountTrace(BYTRACE_TAG_OHOS, "count number", ++num);
+        sleep(1);
+    }
+}
+
+void threadFunc1()
+{
+    StartAsyncTrace(label, "testAsync", 1111);
+    for (int i = 0; i < 5; ++i) {
+        cout << "t1" << endl;
+        sleep(1);
+    }
+}
+
+void threadFunc2()
+{
+    for (int i = 0; i < 5; ++i) {
+        cout << "t2" << endl;
+        sleep(1);
+    }
+    FinishAsyncTrace(label, "testAsync", 1111);
+}
+
+int main()
+{
+    thread t1(threadFunc1);
+    t1.join();
+
+    StartTrace(label, "testStart");
+    sleep(1);
+
+    StartTrace(label, "func1Start", 1); // 打印起始点
+    func1();
+    FinishTrace(label, "");
+    sleep(2);
+
+    thread t2(threadFunc2);
+    t2.join();
+
+    StartTrace(label, "func2Start", 2);
+    func2();
+    FinishTrace(label, "");
+    sleep(2);
+
+    sleep(1);
+    FinishTrace(label, "");
+    func3();
+
+    return 0;
+}