Unity How to CustomType to NetworkSerializable ,Transfer between Server and client

Question

I custom serializable types String Array , learn:

1. tutorials

2.INetworkSerializable

and try it.

I Expect the result is:

<Server Received the RPC #0
#Test Server RPC#:a
Server Received the RPC #1
#Test Server RPC#:a
Server Received the RPC #2
...............................​

But Real Rsult :
Server Received the RPC #0
#Test Server RPC#:a
Server Received the RPC #1
Server Received the RPC #2
Server Received the RPC #3

myPIC

Can Tell me Why, Detail..

///////////////////////////////////////////////////////////////////////////

The code as below

using Unity.Netcode; using UnityEngine;

public class RpcTest : NetworkBehaviour {

private MyCustomStruct mystring;

public override void OnNetworkSpawn()
{
   
    mystring.Array = new string[]{ "a", "b", "c" };
    if (IsClient)
    {
        TestServerRpc(0,mystring);
    }
}

[ClientRpc]
void TestClientRpc(int value,  MyCustomStruct mystring)
{
    if (IsClient)
    {
        Debug.Log("Client Received the RPC #" + value);
        Debug.Log("#Test Client RPC#:" + mystring.Array[0].ToString());
        TestServerRpc(value + 1, mystring);
    }
}

[ServerRpc]
void TestServerRpc(int value, MyCustomStruct mystring)
{
    Debug.Log("Server Received the RPC #" + value);
    Debug.Log("#Test Server RPC#:" + mystring.Array[0].ToString());
    TestClientRpc(value, mystring);
}

public struct MyCustomStruct : INetworkSerializable
{
    public string[] Array;

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        // Length
        int length = 0;
        if (!serializer.IsReader)
        {
            length = Array.Length;
        }

        serializer.SerializeValue(ref length);

        // Array
        if (serializer.IsReader)
        {
            Array = new string[length];
        }

        for (int n = 0; n < length; ++n)
        {
            serializer.SerializeValue(ref Array[n]);
        }
    }
}

}