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

System.ValueTuple<T1, T2>

Represents a 2-tuple, or pair, as a value type.
namespace System { public struct ValueTuple<T1, T2> : IEquatable<(T1, T2)>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<(T1, T2)>, System.ITupleInternal { public T1 Item1; public T2 Item2; public ValueTuple(T1 item1, T2 item2); public bool Equals((T1, T2) other); public int CompareTo((T1, T2) other); } }