internal class Program
{
    private static void Main(string[] args)
    {
        MemoryStream ms = null;
        Customer customer = Customer.GetOneCustomer();

using (ms = new MemoryStream())
        {
            Serializer.Serialize(ms, customer);
            Console.WriteLine("ProtoBuf Length:{0}", ms.Length);
        }
        using (ms = new MemoryStream())
        {
            var formater = new BinaryFormatter();
            formater.Serialize(ms, customer);
            Console.WriteLine("BinaryFormatter Length:{0}", ms.Length);
        }
        using (ms = new MemoryStream())
        {
            var serializer = new XmlSerializer(typeof (Customer));
            serializer.Serialize(ms, customer);
            Console.WriteLine("XmlSerializer Length:{0}", ms.Length);
        }

string xml =
            @"<?xml version=""1.0"" ?>
　<Customer xmlns=""urn:Sep2003Example"">
<CustomerID>ALFKI</CustomerID>
<PO>9572658</PO>
<Address>
    <Street>One Main Street</Street>
    <City>Anywhere</City>
    <State>NJ</State>
    <Zip>08080</Zip>
</Address>
<Order>
    <OrderID>10966</OrderID >
    <LineItem>
        <ProductID>37</ProductID>
        <UnitPrice>26.50 </UnitPrice>
        <Quantity>8</Quantity>
        <Description>Gravad lax </Description>            　
    </LineItem>
    <LineItem>
        <ProductID>56 </ProductID>
        <UnitPrice>38.00</UnitPrice>
        <Quantity>12</Quantity>
        <Description>Gnocchi di nonna Alice</Description>            　
    </LineItem>
</Order>    　
</Customer>";
        Console.WriteLine("xml length:{0}", Encoding.UTF8.GetByteCount(xml));
        Console.ReadKey();
    }
}

[ProtoContract]
[Serializable]
public class Customer {
    [ProtoMember(1)]
    public string CustomerID { get; set; }
    [ProtoMember(2)]
    public int PO { get; set; }
    [ProtoMember(3)]
    public Address Address { get; set; }
    [ProtoMember(4)]
    public Order Order { get; set; }

public static Customer GetOneCustomer() {
        Customer customer = new Customer {
            CustomerID = "ALFKI",
            PO = 9572658,
            Address = new Address {
                Street = "One Main Street",
                City = "Anywhere",
                State = "NJ",
                Zip = 08080
            },
            Order = new Order {
                OrderID = 10966,
                LineItems = new List<LineItem>
                    {
                        new LineItem
                            {
                                ProductID = 37,
                                UnitPrice = 26.50M,
                                Quantity =8,
                                Description ="Gravad lax"
                            },
                        new LineItem
                            {
                                ProductID = 56,
                                UnitPrice = 38.00M,
                                Quantity =12,
                                Description ="Gnocchi di nonna Alice"    
                            }
                    }
            }
        };
        return customer;
    }
}

[ProtoContract]
[Serializable]
public class Address {
    [ProtoMember(1)]
    public string Street { get; set; }
    [ProtoMember(2)]
    public string City { get; set; }
    [ProtoMember(3)]
    public string State { get; set; }
    [ProtoMember(4)]
    public int Zip { get; set; }
}

[ProtoContract]
[Serializable]
public class Order {
    [ProtoMember(1)]
    public int OrderID { get; set; }
    [ProtoMember(2)]
    public List<LineItem> LineItems { get; set; }
}

[ProtoContract]
[Serializable]
public class LineItem {
    [ProtoMember(1)]
    public int ProductID { get; set; }
    [ProtoMember(2)]
    public decimal UnitPrice { get; set; }
    [ProtoMember(3)]
    public int Quantity { get; set; }
    [ProtoMember(4)]
    public string Description { get; set; }
}