SignalR custom ScaleoutMessageBus memory leak - memory-leaks

Question

I implement simple ScaleoutMessageBus. I override Send method and send message to all configured nodes. And It works, but when system is under heavy load memory of w3wp process grows. When I create dump I saw that almost all memory is held in SignalR Message objects. Does any body know what I doing wrong?
Thanks
Martin
Update added ScaleOutBus class
public class ScaleoutMessageBus : Microsoft.AspNet.SignalR.Messaging.ScaleoutMessageBus
{
private static long sNextId = long.MinValue;
private readonly List<string> proxiesEndpointName;
private static readonly object Lock = new object();
/// <summary>
/// Initializes a new instance of the <see cref="ScaleoutMessageBus" /> class.
/// </summary>
/// <param name="resolver">The resolver.</param>
/// <param name="config">The configuration.</param>
public ScaleoutMessageBus(IDependencyResolver resolver, ScaleoutConfiguration config)
: base(resolver, config)
{
proxiesEndpointName = new List<string>(config.NodeEndpoints);
Open(0);
}
private void Received(int streamIndex, long id, byte[] data)
{
ScaleoutMessage message = ScaleoutMessage.FromBytes(data);
var uid = unchecked((ulong)id);
lock (Lock)
{
OnReceived(streamIndex, uid, message);
}
}
/// <summary>
/// Sends the specified stream index.
/// </summary>
/// <param name="streamIndex">Index of the stream.</param>
/// <param name="messages">The messages.</param>
/// <returns></returns>
protected override Task Send(int streamIndex, IList<Message> messages)
{
var messageToSend = new ScaleoutMessage(messages);
var bytesToSend = messageToSend.ToBytes();
return Task.Factory.StartNew(() =>
{
Parallel.ForEach(proxiesEndpointName.Where(s => !String.IsNullOrEmpty(s)), s =>
{
try
{
var proxy = new ChannelProxyWrapper<IBackplaneService>(s).GetTransparentProxy();
proxy.Send(streamIndex, bytesToSend);
}
catch (Exception ex)
{
LogHelper.WriteException(ex, TraceEventType.Warning, "Cannot send message to node {0}", s);
}
});
});
}
/// <summary>
/// Sends the specified stream index.
/// </summary>
/// <param name="streamIndex">Index of the stream.</param>
/// <param name="data">The data.</param>
public void Send(int streamIndex, byte[] data)
{
long id = Interlocked.Increment(ref sNextId);
Received(streamIndex, id, data);
}
}