NServiceBus - Sample that shows the flow of context bag extension data from the incoming to outgoing context

BehaviorContextBagFlow.cs

// LogManager.Use<DefaultFactory>().Level(LogLevel.Debug);
// var pipeline = endpointConfiguration.Pipeline;
// pipeline.Register(new IN(), nameof(IN));
// pipeline.Register(new OUT(), nameof(OUT));

class IN : Behavior<IIncomingLogicalMessageContext>
{
    public const string Key = "count";
    static long count;
    static readonly ILog Log = LogManager.GetLogger<IN>();
    public override Task Invoke(IIncomingLogicalMessageContext context, Func<Task> next)
    {
        var value = Interlocked.Increment(ref count);
        Log.FatalFormat("count: {0}", value);
        context.Extensions.Set(Key, value);
        return next();
    }
}

class OUT : Behavior<IOutgoingLogicalMessageContext>
{
    static readonly ILog Log = LogManager.GetLogger<OUT>();

    public override Task Invoke(IOutgoingLogicalMessageContext context, Func<Task> next)
    {
        var set = context.Extensions.TryGet(IN.Key, out long value);
        Log.FatalFormat("count: {0} {1}", set, value);
        return next();
    }
}