code: public final void patchTraces(String projectId, Traces traces) {
  
      PatchTracesRequest request =
          PatchTracesRequest.newBuilder().setProjectId(projectId).setTraces(traces).build();
      patchTraces(request);
    }
docs: Sends new traces to Stackdriver Trace or updates existing traces. If the ID of a trace that you
  send matches that of an existing trace, any fields in the existing trace and its spans are
  overwritten by the provided values, and any new fields provided are merged with the existing
  trace data. If the ID does not match, a new trace is created.
  
  <p>Sample code:
  
  <pre><code>
  try (TraceServiceClient traceServiceClient = TraceServiceClient.create()) {
  String projectId = "";
  Traces traces = Traces.newBuilder().build();
  traceServiceClient.patchTraces(projectId, traces);
  }
  </code></pre>
  
  @param projectId ID of the Cloud project where the trace data is stored.
  @param traces The body of the message.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails