<PackageReference Include="System.ValueTuple" Version="4.4.0-preview2-25405-01" />

System.ITupleInternal

interface ITupleInternal
Helper so we can call some tuple methods recursively without knowing the underlying types.
namespace System { internal interface ITupleInternal { int Size { get; } int GetHashCode(IEqualityComparer comparer); string ToStringEnd(); } }