Why my file isn't uploaded to Firebase's storage (using c# .NET)

I'm using c# .net and trying to upload a '.png' file to Firebase's storage using the code below. There're no errors, the paths are correct and the program seems to be running well, but the file doesn't exist in Firebase's storage. When I run it, it doesn't stop at my breakpoint located after the "await", but acts like everything is OK and presents the console screen like it finished running... If you have any idea please share it, Thanks!

class Program
{
    static void Main(string[] args)
    {          
        stam();
        Console.ReadLine();
    }

   public async static Task stam()
    {
        var stream = File.Open(@"C:\Users\user\Downloads\qrcode.png", FileMode.Open);

        // Construct FirebaseStorage with path to where you want to upload the file and put it there
        var task = new FirebaseStorage("[mydrive].appspot.com")             
         .Child("qrcode.png")
         .PutAsync(stream);

        // Track progress of the upload
        task.Progress.ProgressChanged += (s, e) => Console.WriteLine($"Progress: {e.Percentage} %");

        // Await the task to wait until upload is completed and get the download url
        var downloadUrl = await task;
        Console.WriteLine(downloadUrl);

        showDetails(downloadUrl);       
    }}