How to serialize and de-serialize the string using XMLFmtStream SerializeMode in AppStateSerializer?

//Serialization
using (var stream = new MemoryStream())
{
    var state2 = new Syncfusion.Runtime.Serialization.AppStateSerializer(SerializeMode.XMLFmtStream, stream);
    state2.SerializeObject("hi", "test1");
    state2.PersistNow();
    byte[] byteArray = stream.GetBuffer();
    UTF8Encoding utf8 = new UTF8Encoding();
    text = utf8.GetString(byteArray);
}
//Deserialization
using (var stream = new MemoryStream())
{
    using (var writer = new StreamWriter(stream))
    {
        byte[] bArray = new UTF8Encoding(true).GetBytes(text);
        stream.Write(bArray, 0, bArray.Length);
        //When AppStateSerializer reads the position, being at end.
        //To set the stream position to 0 to load correctly
        stream.Position = 0;
        var state2 = new Syncfusion.Runtime.Serialization.AppStateSerializer(SerializeMode.XMLFmtStream, stream);
        var deserializeObject = state2.DeserializeObject("hi");
        MessageBox.Show(deserializeObject as String, "Found in Memory Stream");
    }
}

'Serialization
Using stream = New MemoryStream()
    Dim state2 = New Syncfusion.Runtime.Serialization.AppStateSerializer(SerializeMode.XMLFmtStream, stream)
    state2.SerializeObject("hi", "test1")
    state2.PersistNow()
    Dim byteArray() As Byte = stream.GetBuffer()
    Dim utf8 As New UTF8Encoding()
    text = utf8.GetString(byteArray)
End Using
'Deserialization
Using stream = New MemoryStream()
    Using writer = New StreamWriter(stream)
        Dim bArray() As Byte = New UTF8Encoding(True).GetBytes(text)
        stream.Write(bArray, 0, bArray.Length)
        'When AppStateSerializer reads the position, being at end.
        'To set the stream position to 0 to load correctly
        stream.Position = 0
        Dim state2 = New Syncfusion.Runtime.Serialization.AppStateSerializer(SerializeMode.XMLFmtStream, stream)
        Dim deserializeObject = state2.DeserializeObject("hi")
        MessageBox.Show(TryCast(deserializeObject, String), "Found in Memory Stream")
    End Using
End Using