Edited Issue: request.Content.ReadAsMultipartAsync() throws an InvalidOperationException if a part has two Content-Type headers [1168]

If a part of a multipart message contains two Content-Type headers, request.Content.ReadAsMultipartAsync() throws the following:

System.InvalidOperationException: Error parsing MIME multipart body part header byte 115 of data segment System.Byte[]. at System.Net.Http.Formatting.Parsers.MimeMultipartBodyPartParser.<ParseBuffer>d__0.MoveNext() at System.Net.Http.HttpContentMultipartExtensions.MoveNextPart(MultipartAsyncContext context)

I expect a 400 in this case.