Структура описывающая уникальную пару.

Pair

using System;

namespace Links.Core.Structures
{
    /// <summary>
    /// Структура описывающая уникальную пару.
    /// </summary>
    public struct Pair : IEquatable<Pair>
    {
        public readonly ulong Source;
        public readonly ulong Target;

        public Pair(ulong source, ulong target)
        {
            Source = source;
            Target = target;
        }

        static public Pair Create(ulong source, ulong target)
        {
            return new Pair(source, target);
        }

        public override int GetHashCode()
        {
            var hash = 17;
            hash = hash * 31 + (int)Source;
            hash = hash * 31 + (int)Target;
            return hash;
        }

        public override bool Equals(object other)
        {
            return other is Pair && Equals((Pair)other);
        }

        public bool Equals(Pair other)
        {
            return Source == other.Source &&
                   Target == other.Target;
        }
    }
}