Unable to see traces in stackdriver

I am using the following Java code to send a test trace to stackdriver

HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();

GoogleCredential cred = GoogleCredential
    .fromStream(
        getClass().getClassLoader().getResourceAsStream("appengineServiceAccountKey.json"),
        httpTransport,
        jsonFactory)
    .createScoped(CloudTraceScopes.all());

CloudTrace gceTrace = new CloudTrace.Builder(httpTransport, jsonFactory, cred)
    .setApplicationName("Google Cloud Trace test app")
    .build();


TraceSpan span = new TraceSpan();
span.setName("foo-bar");
span.setSpanId(new BigInteger("1"));
span.setStartTime("2017-04-02T16:12:03.636Z");
span.setEndTime("2017-04-02T16:12:04.636Z");
Trace trace = new Trace();
trace.setTraceId(UUID.randomUUID().toString().replaceAll("-","")); // Mandatory
trace.setSpans(Collections.singletonList(span));
Traces traces = new Traces();
traces.setTraces(Collections.singletonList(trace)); // Mandatory
cloudTraceService.projects().patchTraces("myproject", traces);

However I don't see anything when I access the trace from console.

https://console.cloud.google.com/traces/details/8289f38bcb6e44c5b30c98953bee0018?project=myproject

Am I missing something ovious ?

Note - I am following the code mentioned in How to do a simple Google Cloud Trace request in Java

UPDATE

I tried the equivalent payload from the API explorer and it gave me 200 response, still no sign of the trace in the Stackdriver console.

Following was my payload

PATCH https://cloudtrace.googleapis.com/v1/projects/myproject/traces?key={YOUR_API_KEY}

{
 "traces": [
  {
   "projectId": "myproject",
   "spans": [
    {
     "startTime": "2017-04-03T16:12:03.636Z",
     "endTime": "2017-04-03T16:12:04.636Z",
     "spanId": "2"
     "name": "bar-foo"
    }
   ],
   "traceId": "8289f38bcb6e44c5b30c98953bee0018"
  }
 ]
}

Response

200

- Show headers -

{
}

Console

Update:

Thanks to someone in GCP community slack who pointed out that the Span Name is missing in the payload to be able to see it in trace console. I have update the code here. However I am stil not able to see the trace , when I send a it from java code even after setting the span name.

Is there any way to check what payload is being sent when the above java code is triggered ?

Finally I figured out that I was not invoking pt.execute() the request after building it

PatchTraces pt =cloudTraceService.projects().patchTraces("myproject", traces);

pt.execute()

reference patchTraces#examples