How to find source file of .net Built in functions like WriteLine()

I'm trying to view the source code of some built in c# functions and trying to explore System.Console class etc.. I used ctrl+click by hovering over the built-in functions like ReadLine(). On using ctrl+click it redirects me to System.Console metadata page -> where I could find only a declaration is available

    // Summary:
    //     Writes the specified string value, followed by the current line terminator, to
    //     the standard output stream.
public static void WriteLine(string value);

In the above case, the function is only declared but couldn't find any definition. So, could someone please help with this? Is there any way to find out the source code definitions of built-in c# functions?