using System;

using Google.Protobuf.WellKnownTypes;

​

public class Program

{

    public static void Main()

    {

        // Now

        var lastWeek = DateTime.Today.AddDays(-7).ToUniversalTime().ToTimestamp();

        var nextWeek = DateTime.Today.AddDays(7).ToUniversalTime().ToTimestamp();

        Console.WriteLine(lastWeek.Seconds);

        Console.WriteLine(nextWeek.Seconds);

        // Better

        var lastWeek2 = DateTimeOffset.UtcNow.AddDays(-7);

        var nextWeek2 = DateTimeOffset.UtcNow.AddDays(7);

        Console.WriteLine(lastWeek2.ToUnixTimeSeconds());

        Console.WriteLine(nextWeek2.ToUnixTimeSeconds());

    }

}