Added assertion to file descriptor close
Added assertion to file descriptor close

PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk