add test: PayloadTest

src/main/java/component/Payload.java

@@ -16,6 +16,9 @@ public class Payload implements TlvComponentBase,InitialAble, IEncodingAble {
     // 成员变量
     private byte[] value;
 
+    public Payload(){
+    }
+
     /**
      * 构造函数
      * @param block

src/main/java/encoding/Encoder.java

@@ -16,6 +16,8 @@ public class Encoder {
     public boolean isEstimator;// 是否仅测量编码后的长度，而不实际进行编码
     public SizeT totalReserve; // 编码缓存数组的大小
 
+    public static final int MaxPacketSize=8800;
+
     /**
      * 编码测量初始化
      * @Description: