Hi Sam,
My guess is cproj is targeting the 4.0 runtime version.
The 4.0 build is missing some files, this is fixed already but is not
released yet. See
https://github.com/restsharp/RestSharp/pull/273 for
details.
You could either:
A. Change the target runtime to 3.5.
B. Checkout the master branch of RestSharp and compile it yourself.
C. Wait for the fix to be released.
Regards,
Bert