Entity UUID

EntityUuid.cs

[Serializable]
[StructLayout(LayoutKind.Explicit)]
public struct EntityUuid : IComparable, IComparable<EntityUuid>, IComparable<Guid>, IEquatable<EntityUuid>, IEquatable<Guid>
{
    [SerializeField]
    [FieldOffset(0)]
    private long _firstHalf;

    [SerializeField]
    [FieldOffset(8)]
    private long _secondHalf;

    [FieldOffset(0)]
    private readonly Guid _guid;
    
    public EntityUuid(string explicitName)
    {
        if (explicitName == null)
        {
            CreateProceduralUuid();
        }
        else
        {
            CreateExplicitUuid(explicitName)
        }
    }

    // ...
}