S09_Handling_duplicates.cs

using System;
using System.Threading.Tasks;

using Streamstone;

namespace Example.Scenarios
{
    public class S09_Handling_duplicates : Scenario
    {
        public override async Task RunAsync()
        {
            var result = await Stream.WriteAsync(new Stream(Partition), new EventData(EventId.From("42")));

            try
            {
                var events = new[]
                {
                    new EventData(EventId.From("56")),
                    new EventData(EventId.From("42"))  // conflicting (duplicate) event
                };

                await Stream.WriteAsync(result.Stream, events);
            }
            catch (DuplicateEventException)
            {
                Console.WriteLine("Duplicate event detection is based on ID of the event.");
                Console.WriteLine("An ID of conflicting event will be reported back as a property of DuplicateEventException.");
                Console.WriteLine("The caller can use this information to remove conflicting event from the batch and retry (or cancel)");
            }
        }
    }
}