Async Parallel Collection Projections

asyncparallelquery.cs

public struct FromAsyncTaskResult{
   public int result;
};

void Main(){
  MainNew().GetAwaiter().GetResult();
}

async Task<FromAsyncTaskResult[]> MainNew()
{

  var bag = new List<FromAsyncTaskResult>();
  var slim = new SemaphoreSlim(1,5);
	// Truncate observable sequence after receiving 5 events 
  
var tasks = 
   Enumerable.Range(0,10)
  			 .AsParallel()
             .Select(async (f)=>
             {  
                slim.Wait();  
				
                try{    
                
                Console.WriteLine(string.Format("[{0}]-{2}  {1}",Thread.CurrentThread.ManagedThreadId, f, DateTime.Now));
                await Task.Delay(1000);
                
                return new FromAsyncTaskResult
                {
				result = await Observable.FromAsync(async ()=> await
                  Task.Run(async ()=> await  Task.FromResult(f)).ConfigureAwait(false)
				  )
                };
                
              } finally {
                slim.Release();
              }
  			});

  var tasksQueryStartAll =  tasks.Select(
                           async (x)=>{ 
                              return await x.ConfigureAwait(false);
                             }).ToArray();

  
  tasksQueryStartAll.Dump();
  return await Task.WhenAll(tasksQueryStartAll); 
}

   //block thread...