WebAPI无法解析多部分/表单-数据post

I'm trying to accept a post from a client (iOS app) and my code keeps failing on reading the stream. Says the message is not complete. I've been trying to get this working for hours it seems like something is wrong in my message format or something. All I'm trying to do is read a string but the developer I'm working with who is doing the iOS part only knows how to send multipart/form-data not content-type json.I'm trying to accept a post from a client (iOS