Should not store empty file when calling DataSubmissionService.GetSubmissionData multiple times

Description

1. Override DataSubmissionService

public class CustomDataSubmissionService: DataSubmissionService
    {
        protected override Submission GetSubmissionData(NameValueCollection rawSubmittedData, FormContainerBlock formContainer, HttpContextBase httpContext, bool isFinalized)
        {
            var result = base.GetSubmissionData(rawSubmittedData, formContainer, httpContext, isFinalized);
            result = base.GetSubmissionData(rawSubmittedData, formContainer, httpContext, isFinalized);
 
            return result;
        }
    }

2. In initialization module (DependencyResolverInitialization.cs)

context.Services.AddSingleton<DataSubmissionService, CustomDataSubmissionService>();

3. Create a form with UploadFile.
4. Try to submit the form with upload file > File is saved twice (one is empty).