How to transfer a complex object containing stream as a member from web API service layer to client controller

public class FileStreamDto
    {
        public FileStreamDto(){}}
        public string Name { get; set; }
        public Stream Data { get; set; }
    }

DataContractJsonSerializer

Type 'System.Net.Http.WinHttpResponseStream' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. Alternatively, you can ensure that the type is public and has a parameterless constructor - all public members of the type will then be serialized, and no attributes will be required.

public async Task<IActionResult> Download([FromQuery]Guid fileId)
        {
            try
            {
                var downloadResponse = await _documentProxy?.GetFile(fileId);
                var type = downloadResponse.Body.GetType();
                DataContractJsonSerializer dcj = new DataContractJsonSerializer(new FileStreamDto().GetType());
                var ms = new MemoryStream();
                dcj.WriteObject(ms, downloadResponse.Body.Data);
                var response = File(ms, "application/octet-stream", downloadResponse.Body.Name);
                return response;
            }
            catch (Exception ex)
            {
                //log and send a custom error to service
                throw new Exception($"Unable to retrieve document for {fileId}");
            }
        }