will runtime use new thread in each API request or all are same thread?

[ljzj2]

I wonder if the runtime will use new thread when a request comes. if so I think there is no difference between use or not use async .

if there is function :

public async Task<int> Get(int id)
{
    id = 0;

   id= await db.Values.GetAsync(x => x.Id == id);

    id++;

    return id;
}

then it will be:

public async Task<int> Get(int id)
 {
     int value = 0;

     void perform()
     {
         switch (value)
         {
             case 0:
                 id = 0;
                 value++;
                 perform();
                 break;
             case 1:
//I do not sure
                 db.Values.Get(x => x.Id == id).ContinueWith(() =>
                 {
                     value++;
                     perform();
                 });

// I do not sure if it will be this code:
ThreadPool.QueueUserWorkItem((obj) =>
{
    db.Values.Get(x => x.Id == id).ContinueWith(() =>
    {
        value++;
        perform();
    });
});
                 break;
             case 2:
                 id++;
                 break;
         }
     }

     perform();

     return id;
}

if each request comes the runtime use new thread I think not use async is same to use.