public static async Task <HttpResponseMessage> UserChirpsPost(
            [HttpTrigger(AuthorizationLevel.Function, "post", Route = "user/{userId}/chirps")] HttpRequestMessage req,
            [DurableClient] IDurableClient client,
            ILogger log,
            string userId)
        {
            Authenticate(req, userId);
            var chirp = new Chirp()
            {
                UserId    = userId,
                Timestamp = DateTime.UtcNow,
                Content   = await req.Content.ReadAsStringAsync(),
            };
            await client.SignalEntityAsync <IUserChirps>(userId, x => x.Add(chirp));

            return(req.CreateResponse(HttpStatusCode.Accepted, chirp));
        }
 public void Add(Chirp chirp)
 {
     Chirps.Add(chirp);
 }