Save file to specific folder in Amazon AWS S3 Bucket in ASP.Net Core

Hi,

The code below will successfully save in S3 bucket but how can I specify to save under a specific folder?

public async Task<IActionResult> UploadFileToS3(IFormFile file)
 {

     var credentials = new BasicAWSCredentials("access key id", "secret access key");

     using (var amazonS3Client = new AmazonS3Client(credentials, RegionEndpoint.APSouth1))
     {
         using (var memorystream = new MemoryStream())
         {
             file.CopyTo(memorystream);
             var request = new TransferUtilityUploadRequest
             {
                 InputStream = memorystream,
                 Key = file.FileName,
                 BucketName = "myaspstorage",
                 ContentType = file.ContentType,
             };

             var transferUtility = new TransferUtility(amazonS3Client);
             await transferUtility.UploadAsync(request);
         }

     }

     S3FileDetails fileDetails = new S3FileDetails();
     fileDetails.FileName = file.FileName;
     fileDetails.Filedate = DateTime.Today;

     _db.S3FileDetails.Add(fileDetails);
     _db.SaveChanges();

     ViewBag.Success = "File uploaded to S3 Bucket successfully!";
     return RedirectToAction(nameof(Index));
 }