Calling external api using JsonClient

[rhemasystems]

Hi All,
Please am using JsonClient from serenity endpoint to call an external api as below:
it works perfectly except that Serenity doesnt wait for the external call to be completed before executing other codes in the endpoint class.
Even if I use ServiceResponse, its still the same
Please is there something I am missing here.

var client = new JsonServiceClient("http://app.boxing.com");
var response = client.Post<ClientResponse>("api/econnect/PostVendor", new Econnect { ReqId = Convert.ToInt32(request.RequestId), ReqType = "VEND" });

if (response.Success)
{
    Console.WriteLine("successful: " + response.Message);
}

public class ClientResponse
   {
       public bool Success { get; set; }
       public string Message { get; set; }
   }