Async, await for running process that executes SSRS report and generates pdf 1000 times

Hi,

I have API end point that gets called from another service(bl1).

[HttpGet]

[Route("createfile")]

public void createsfile(string param1, string param2)

{

//asynchronous call to bl1 method

 var files = new bl1();

 files.generateFiles(param1, param2);

 //send message to the caller that file creation process started immediately.

}

New Service (bl1)

public void generatefiles (string param1, string param2)

{

//loop through accounts that were retrieved from database

foreach (int act in actlist)

{

      //generate stream by calling SSRS web request.

      

 try
            {
                HttpClient client = new HttpClient(new HttpClientHandler()
                { UseDefaultCredentials = true,/* PreAuthenticate = false  */});

                Stream theStream =  await client.GetStreamAsync(new Uri(reportUrl));
                using (var memoryStream = new MemoryStream())
                {
                    theStream.CopyTo(memoryStream);
                    System.IO.File.WriteAllBytes(pFileName, memoryStream.ToArray());
                }
            }
            catch (Exception ex)
            {
                string he = "routine";
            }

 }

}

From this end point, we need to call another service say bl1 (business logic) that actually generates 2000 files. What I want is when request is made to the end point, it should start bl1 process asynchronously and immediately go back to caller with message that 'process started'

That bl1 process should be asynchronous loop through accounts and generate pdf for all accounts ( may be 1000 times)

How can I do without using await or async. Only main end point needs to be async because it needs to be started on new thread and main thread not to worry about it.