Convert S3 response file to object using System.Text.Json

Question

I'm trying to deserialize a response stream from AWS S3 (a JSON file) to an object using System.Text.Json.

  using var file = await _s3.GetObjectAsync(new GetObjectRequest { BucketName = bucketName, Key = key });
  var memoryStream = new MemoryStream();
  using var responseStream = file.ResponseStream;
  responseStream.CopyTo(memoryStream);
  var objExample = await JsonSerializer.DeserializeAsync<ObjectExample>(memoryStream);

The error I got is:

'The input does not contain any JSON tokens. Expected the input to start with a valid JSON token, when isFinalBlock is true. Path: $ | LineNumber: 0 | BytePositionInLine: 0.'