message: filter out tfstreamz plane when generate trace events.
diff: @@ -249,12 +249,19 @@ void SortXSpace(XSpace* space) {
  for (XPlane& plane : *space->mutable_planes()) SortXPlane(&plane);
  }
  +// Normalize the line's timestamp in this XPlane.
  +// NOTE: This can be called multiple times on the same plane. Only the first
  +// call will do the normalization, subsequent calls will do nothing.
  +// The assumption is that both line's timestamp_ns and start_time_ns are
  +// nano-seconds from epoch time, the different of these values is much
  +// smaller than these value.
  void NormalizeTimestamps(XPlane* plane, uint64 start_time_ns) {
  for (XLine& line : *plane->mutable_lines()) {
  - DCHECK_GE(line.timestamp_ns(), start_time_ns);
  + if (line.timestamp_ns() >= start_time_ns) {
  line.set_timestamp_ns(line.timestamp_ns() - start_time_ns);
  }
  }
  +}
  void NormalizeTimestamps(XSpace* space, uint64 start_time_ns) {
  for (XPlane& plane : *space->mutable_planes()) {
  