public class someFunction
    {
        [FunctionName("someFunction")]
        public async Task<List<string>> RunOrchestrator(
            [OrchestrationTrigger] IDurableOrchestrationContext context)
        {
            var outputs = new List<string>();

            // Replace "hello" with the name of your Durable Activity Function.
            outputs.Add(await context.CallActivityAsync<string>("someFunction_Hello", "Tokyo"));
            outputs.Add(await context.CallActivityAsync<string>("someFunction_Hello", "Seattle"));
            outputs.Add(await context.CallActivityAsync<string>("someFunction_Hello", "London"));

            // returns ["Hello Tokyo!", "Hello Seattle!", "Hello London!"]
            return outputs;
        }

        public class Activities
        {

            [FunctionName("someFunction_Hello")]
            public string SayHello([ActivityTrigger] string name, ILogger log)
            {
                log.LogInformation($"Saying hello to {name}.");
                return $"Hello {name}!";
            }
        }
}