hello-world C# Lambda function

hello.cs

using Amazon.Lambda.Core;

[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace HelloWorld
{
    public class Function
    {
        public string FunctionHandler(string input, ILambdaContext context)
        {
            return "Hello World!";
        }
    }
}