SingleMessageOrderTest.cs

using Microsoft.Azure.EventHubs;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Azure.WebJobs.ServiceBus;
using StackExchange.Redis;
using System;
using System.Threading.Tasks;

namespace OrderedEventHubs
{
    public static class EventHubTrigger
    {
        private static ConnectionMultiplexer redis = ConnectionMultiplexer.Connect(Environment.GetEnvironmentVariable("Redis"));
        private static IDatabase db = redis.GetDatabase();

        [FunctionName("SingleMessageTrigger")]
        public static async Task Single(
          [EventHubTrigger("ordered", Connection = "EventHub")] EventData eventData, 
          TraceWriter log)
        {
            try
            {
                await db.ListRightPushAsync(
                    "events:" + eventData.Properties["partitionKey"], 
                    (string)eventData.Properties["counter"]);
            }
            catch
            {
                // handle event exception
            }
        }
    }
}