Invariant String Interpolation

Example.cs

namespace SomeLib
{
    using System.Globalization;
    using System.Runtime.CompilerServices;

    static partial class StringInterpolation
    {
        // This is to allow to use fast string interpolation
        public static string FastInvariantInterpolation(ref DefaultInterpolatedStringHandler handler)
        {
          return string.Create(CultureInfo.InvariantCulture, ref handler);
        }

        // This is how FormattableString.Invariant works
        public static string SlowInvariantInterpolation(FormattableString fs)
        {
          return fs.Format(CultureInfo.InvariantCulture, GetArguments());
        }
    }
}