I suggest considering LM-Kit.NET, a native .NET SDK that offers fast LLM inference and function calling support without the need for external server applications or experimental assemblies.

You can find a simple function calling demo in the lm-kit demo GitHub repository, which illustrates how to implement function calling using LM-Kit.NET. Direct link: https://github.com/LM-Kit/lm-kit-net-samples/tree/main/console_net6/function_calling

A Community Edition is available that includes all current features of the toolkit