这是我用来获取对象的函数，我想获取通过预签名 url 获取的对象并将其放入流中以转换为 base64 并将其作为 base64 发送到前端

  public async Task<Stream> GetFile(string path)
    {
        using (IAmazonS3 client = new AmazonS3Client(_configuration.Getvalue<string>("AWS:accessKey"),_configuration.Getvalue<string>("AWS:secretKey"),bucketRegion))
        {
            var filetransferutility = new TransferUtility(client);
            path = path.Remove(0,BaseUrl.Length);
            GetPreSignedUrlRequest request = new GetPreSignedUrlRequest
            {
                BucketName = _configuration.Getvalue<string>("AWS:bucketName"),Key = path,Verb = HttpVerb.GET,Expires = DateTime.Now.AddMinutes(5)
            };

            //signe url generated for the object 
            string signedpath = client.GetPreSignedURL(request);

            //var stream = await filetransferutility.OpenStreamAsync(_configuration.Getvalue<string>("AWS:bucketName"),signedpath);

            //i want this stream to be filled with the object i get from presigned URL,can i do that ?
            return stream;
        }
    }