public async Task TrackEventFailsWithoutIdentity()
 {
     var customerIo = new CustomerIo(SiteId, ApiKey);
     await Assert.ThrowsAsync <CustomerIoApiException>(async() =>
                                                       await customerIo.TrackEventAsync("signup", new
     {
         Group    = "trial",
         Referrer = "email campaign"
     }));
 }
 public async Task TrackEvent()
 {
     var customerIo = new CustomerIo(SiteId, ApiKey);
     await customerIo.TrackEventAsync("signup", new
     {
         Group    = "trial",
         Referrer = "email campaign"
     },
                                      null,
                                      "from_static_identity");
 }