SNS Load Testing Code

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Amazon.SimpleNotificationService;
using Newtonsoft.Json;

namespace sns_load_test
{
    class Program
    {
        //Change this to control what SNS topic you are publishing to
        const string TopicArn = "arn:aws:sns:ap-southeast-2:xxxxxxxxxxxxxxxxxxxx";
        //Change this to control how many messages to send in the load test
        const int NumberOfMessagesToSend = 100;

        static void Main(string[] args)
        {
            Run().Wait();
        }

        static async Task Run()
        {
            List<string> serializedMessages = new List<string>();
            for (int i = 0; i < NumberOfMessagesToSend; i++)
            {
                //Customise the content of your SNS messages as need be here
                var message = new {
                    Property = "Hello World!"
                };

                serializedMessages.Add(JsonConvert.SerializeObject(message));
            }

            var snsClient = new AmazonSimpleNotificationServiceClient(Amazon.RegionEndpoint.APSoutheast2);
            IEnumerable<Task> tasks = serializedMessages.Select(async serializedMessage =>
            {
                try
                {
                    await snsClient.PublishAsync(TopicArn, serializedMessage);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            });

            await Task.WhenAll(tasks);

            Console.WriteLine("Done!");
        }
    }
}

sns-load-test.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <RootNamespace>sns_load_test</RootNamespace>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="AWSSDK.SimpleNotificationService" Version="3.3.2.10" />
    <PackageReference Include="Newtonsoft.Json" Version="10.0.3" />
  </ItemGroup>
</Project>