[ServiceContract]
public interface IService1
{

	[OperationContract]
	void AddData(IEnumerable<double> values);

	[OperationContract]
	IEnumerable<double> GetData();
}

[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
public class Service1 : IService1
{
	Queue<double> _q = new Queue<double>();
	ConcurrentQueue<double> _qq = new ConcurrentQueue<double>();

	public void AddData(IEnumerable<double> values)
	{
		foreach (var val in values)
		{
			_q.Enqueue(val);
			//_qq.Enqueue(val);

			Thread.Sleep(500);
		}
	}

	public IEnumerable<double> GetData()
	{
		return _q;
		//return _qq;
	}
}

namespace ConsoleApplication1
{
    class Program
    {
        static double[] v1 = new double[] { 1, 11, 111, 1111 };
        static double[] v2 = new double[] { 2, 22, 222, 2222 };
        static double[] v3 = new double[] { 3, 33, 333, 3333 };
        static double[] v4 = new double[] { 4, 44, 444, 4444 };

        static void Main(string[] args)
        {
            Service1Client client = new Service1Client();

            //client.AddData(v1);
            //client.AddData(v2);
            //client.AddData(v3);
            //client.AddData(v4);

            client.AddDataAsync(v1);
            client.AddDataAsync(v2);
            client.AddDataAsync(v3);
            client.AddDataAsync(v4);

            Console.WriteLine("Data has been sended.");

            Console.ReadKey();

            Console.WriteLine("This is your data:");

            foreach (var v in client.GetData())
                Console.WriteLine(v);

            Console.ReadKey();
        }
    }
}