example: add struct pointer example

Author: xiaojian-hong

Diff for: examples/high_level/struct_pointer/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/yomorun/y3-codec-golang"
+)
+
+// Example of encoding and decoding struct type.
+func main() {
+	// Simulate source to generate and send data
+	data := &NoiseData{Noise: 40, Time: time.Now().UnixNano() / 1e6, From: "127.0.0.1"}
+	fmt.Printf("encoded data: %v\n", *data)
+	sendingBuf, _ := y3.NewCodec(0x10).Marshal(data)
+	source := y3.FromStream(bytes.NewReader(sendingBuf))
+	// Simulate flow listening and decoding data
+	var decode = func(v []byte) (interface{}, error) {
+		var obj NoiseData
+		err := y3.ToObject(v, &obj)
+		if err != nil {
+			return nil, err
+		}
+		return obj, nil
+	}
+	consumer := source.Subscribe(0x10).OnObserve(decode)
+	for item := range consumer {
+		fmt.Printf("observed data: %v\n", item)
+	}
+}
+
+type NoiseData struct {
+	Noise float32 `y3:"0x11"`
+	Time  int64   `y3:"0x12"`
+	From  string  `y3:"0x13"`
+}