PGO is a native compilation technology used by the C++ compiler to generate better optimized code.  

Sublime Text plugin for performing quick inline calculations with a simple keypress (Alt+C)

A Multitasking monolithic Kernel based x86 targeting Operating System written in C# from scratch 

As a matter of implementation details, C# tuples are implemented on top of ValueTuple types. 

A .Net CIL generation helper (for when C# isn’t fast enough) 

State / Direction of C# as a High-Performance Language (Roslyn GitHub Issue #10378) 

Learn how to integrate the CefSharp open-source web browser into a C# WinForms app 

A practical analysis of the new features of C# 6: Part 2