Nuget Package both source and dlls

[vikigenius]

I want to create a .Net class library and allow the users the option to either use the DLL or the C# source directly.

I know you can use contentFiles to include sources. But it does not work well with SDK style projects. The included source is used as a content file, not included in build. See this question

Another idea I had was if you could control the <IncludeAssets> node upon install, I can set it to include only the DLL by default and allow users to override if they want to use sources. This SO question suggests it's impossible.

Another idea is to create two packages. One called Foo and another called Foo.Sources. But this doesn't seem easy to do and there doesn't seem to be any example workflows that make this easy?

So ultimately, I am out of ideas. Any suggestions/resources/help is appreciated.