我需要創建一個Packet的Script來處理Packet的資訊，在伺服器或是客戶端進行封包傳輸前，需先將所有 Data type 轉成bytes，並將其儲存到 Buffer中。

一. 初始化

private List<byte> buffer;
private byte[] readableBuffer;
private int readPos;
/// <summary>Creates a new empty packet (without an ID).</summary>
public Packet()
{
    buffer = new List<byte>(); // Initialize buffer
    readPos = 0; // Set readPos to 0
}
/// <summary>Creates a new packet with a given ID. Used for sending.</summary>
/// <param name="_id">The packet ID.</param>
public Packet(int _id)
{
    buffer = new List<byte>(); // Initialize buffer
    readPos = 0; // Set readPos to 0
    Write(_id); // Write packet id to the buffer
}
/// <summary>Creates a packet from which data can be read. Used for receiving.</summary>
/// <param name="_data">The bytes to add to the packet.</param>
public Packet(byte[] _data)
{
    buffer = new List<byte>(); // Initialize buffer
    readPos = 0; // Set readPos to 0
    SetBytes(_data);
}

二. 撰寫封包資料
不同的資料型態都需要用BitConverter轉換成Bit來寫入封包 (不包括中文)。

public void Write(int _value)
{
    buffer.AddRange(BitConverter.GetBytes(_value));
}

如果是中文字的話比較特別，要用到Encoding。

public void Write(string _value)
{
    byte[] _bytes = Encoding.UTF8.GetBytes(_value);
    Write(_bytes.Length); // Add the length of the string to the packet
    buffer.AddRange(_bytes); // Add the string itself
}

三. 讀取封包資料

public int ReadInt(bool _moveReadPos = true)
{
    if (buffer.Count > readPos)
    {
        // If there are unread bytes
        int _value = BitConverter.ToInt32(readableBuffer, readPos); // Convert the bytes to an int
        if (_moveReadPos)
        {
            // If _moveReadPos is true
            readPos += 4; // Increase readPos by 4
        }
        return _value; // Return the int
    }
    else
    {
        throw new Exception("Could not read value of type 'int'!");
    }
}