StackExchange.Redis-ExpiryCounters.cs

    class Program
    {
        static ConnectionMultiplexer redisConnection = ConnectionMultiplexer.Connect("<REDIS connection string>");
        static void Main(string[] args)
        {
            var key = "counter.test";
            var expiry = TimeSpan.FromMinutes(5);
            IDatabase db = redisConnection.GetDatabase(3);
            
            var count = db.StringIncrement(key, 1);
            var ttl = db.KeyTimeToLive(key);

            if (!ttl.HasValue)
            {
                db.KeyExpire(key, expiry);
                ttl = expiry;
            }

            Console.WriteLine($"Count: {count}");
            Console.WriteLine($"TTL(s): {ttl.Value.TotalSeconds}");

            Console.ReadLine();

        }
    }