Runtime error with System.Net.Http.Formatting 5.2.3

[chriseldredge]

It appears that WebApi added an overload to WriteToStreamAsync that accepts a CancellationToken parameter. JsonpMediaTypeFormatter does not implement this overload, so the following error is thrown at runtime when attempting to serialize a response:

The media type formatter of type 'JsonpMediaTypeFormatter' does not support writing because it does not implement the WriteToStreamAsync method.