C# How to create thread based pipe line

Question

I was searching google to create a thread based pipe line and i found the below incomplete code. please see the code and please discuss how it would be working ?

the code is incomplete. so it will be great help if any one create a sample scenario with the below incomplete code.

public class OnFetchEvent : AsyncEvent {}
public class OnDecodeEvent : AsyncEvent {}
public class OnExecuteEvent : AsyncEvent {}
public class OnWritebackEvent : AsyncEvent {}

public class FetchObserver : Observer,
   IObserve<OnFetchEvent>
{
   public void OnEvent(OnFetchEvent @event)
   {
      ....do some stuff

      // raise the next event
      RaiseEvent<OnDecodeEvent>(); 
   }
}

public class Pipeline
{
   public void RaiseEvent<TEvent>()
   {
      if (typeof(TEvent) is AsyncEvent)
        ...create thread and raise the event which will notify the appropriate 
           observers of the event in the newly created thread
   }

  }

Usage:

pipeline.RegisterObserver<FetchObserver>()
  .AndObserver<DecodeObserver>()
  .AndObserver<ExecuteObserver>()
  .AndObserver<WriteBackObserver>();

pipeline.RaiseEvent<OnFetchEvent>();

at all the above code has any relation with thread ?. with my small understanding it seems it is event based with Observer. please some one create a sample example with above code.

Thanks