switch to .net framework 4.6.1 and back
<PropertyGroup>
<TargetFramework>netcoreapp1.1</TargetFramework>
</PropertyGroup>
<PropertyGroup>
<TargetFramework>net461</TargetFramework>
</PropertyGroup>
#if NETCOREAPP1_1
return "Hello world!";
#elif NET461
return Assembly.GetExecutingAssembly().FullName;
#endif