SendBol

batch.cs

 public void Batch()
  {
      var batchOne = GetBatch(1000, "Origin1", "Dest1", "Carrier1", DateTime.Now.AddDays(-1), DateTime.Now.AddHours(-1));

      foreach (var item in batchOne)
      {
          SendBol(item);
      }

      var threadId = Thread.CurrentThread.ManagedThreadId;
      for (int i = 0; i < 20; i++)
      {
          Thread.Sleep(TimeSpan.FromSeconds(1));
          _output.WriteLine("thread: " + threadId + ", debug: " + i);
      }
  }

  private List<BolConstraint> GetBatch(int count, string origin, string dest, string carrierId, DateTime puDate, DateTime timestamp)
  {
      var rtn = new List<BolConstraint>();

      for (int i = 0; i < count; i++)
      {
          var item = new BolConstraint
          {
              Origin = "origin1",
              Destination = "dest1",
              CarrierId = "2",
              PickupDate = new DateTime(2018, 10, 1),
              Timestamp = DateTime.Now
          };

          rtn.Add(item);
      }

      return rtn;
  }

BolConstraint.cs

  public class BolConstraint
  {
      public string Origin;
      public string Destination;
      public string CarrierId;
      public DateTime PickupDate;
      public DateTime Timestamp;
  }

first.cs

 public class Temp
  {
      private readonly ITestOutputHelper _output;

      public Temp(ITestOutputHelper output)
      {
          _output = output;
      }
      
      [Fact]
      public void First()
      {
          var item = new BolConstraint
          {
              Origin = "origin1",
              Destination = "dest1",
              CarrierId = "1",
              PickupDate = new DateTime(2018, 10, 1),
              Timestamp = DateTime.Now
          };

          SendBol(item);

          for (int i = 0; i < 20; i++)
          {
              Thread.Sleep(TimeSpan.FromSeconds(1));
              _output.WriteLine("debug: " + i);
          }
      }

      async Task SendBol(BolConstraint constraint)
      {
          await Task.Delay(TimeSpan.FromMinutes(15))
                    .ConfigureAwait(false);

          // get records based on constraint
          // send records as bol with single shipperShipmentId
          // update records
      }
  }
}

second.cs

  [Fact]
    public void Second()
    {
        var item1 = new BolConstraint
        {
            Origin = "origin1",
            Destination = "dest1",
            CarrierId = "1",
            PickupDate = new DateTime(2018, 10, 1),
            Timestamp = DateTime.Now
        };

        var item2 = new BolConstraint
        {
            Origin = "origin1",
            Destination = "dest1",
            CarrierId = "2",
            PickupDate = new DateTime(2018, 10, 1),
            Timestamp = DateTime.Now
        };

        SendBol(item1);
        SendBol(item2);

        var threadId = Thread.CurrentThread.ManagedThreadId;
        for (int i = 0; i < 20; i++)
        {
            Thread.Sleep(TimeSpan.FromSeconds(1));
            _output.WriteLine("thread: " + threadId + ", debug: " + i);
        }
    }