Why is my sessionful,NetTcpBinding, Streaming service instance not retaining session state?

See more:

C#

WCF

Binding

streaming

I am trying to figure out why my NetTcpService is not maintaining state, as expected. (Perhaps I did it wrong)

I have a WCF service with the following structure(simplified):

Contract:

ServiceContract(SessionMode = SessionMode.Allowed)]
public interface IMyService
{
    [OperationContract]
    void Init(StreamMetaData metaData);

    [OperationContract]
    StreamMetaData GetMetaData();

}

Implementation

[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession,ConcurrencyMode = ConcurrencyMode.Multiple)]
public class MyService : IMyService
{
    private StreamMetaData _streamMetaData;
    private StreamMetaData StreamMetaData
    {
        get { return this._streamMetaData; }
        set { this._streamMetaData= value; }

    }

    public void Init(StreamMetaData metaData)
    {
        if (metaData == null)
            throw new ArgumentNullException("metaData");
        try
        {
            this.StreamMetaData = metaData;
        }
        catch (Exception ex)
        {
            throw ex;
        }

    }

    public StreamMetaData GetMetaData()
    {
        return this.StreamMetaData;

    }
}

Client Side

MyServiceNetTcp.MyServiceClient client= new MyServiceNetTcp.MyServiceClient ();

client.Open();

//metaData is an instance of StreamMetaData initialised somewhere in the code
client.Init(metaData);

var currentMetaData = client.GetMetaData(); //Returns null

I followed the MSDN documentation on handling sessions[^]MSDN documentation on handling sessions (streams specifically - last paragraph).

Why is it that var currentMetaData = client.GetMetaData(); returns null? Despite initializing it in the first call?