public void Unsubscribe(string channelName)
{
if (!IsConnected) return;
Imb.UnSubscribe(channelName);
// Remove from map of known reception serializers.
if (channelSerializers.ContainsKey(channelName)) channelSerializers.Remove(channelName);
if (channelCallbacks.ContainsKey(channelName)) channelCallbacks.Remove(channelName);
}