t.Logf("got span %+v, want span %+v", got, want)
		return false
	}
	if len(got.ChildSpans) < len(want.ChildSpans) {
		t.Logf("got %d child spans from, want %d child spans, maybe trace has not be fully reported",
			len(got.ChildSpans), len(want.ChildSpans))
		return false
	} else if len(got.ChildSpans) > len(want.ChildSpans) {
		t.Logf("got %d child spans from, want %d child spans, maybe destination rule has not became effective",

			for c := range spans {
				if spans[c].ParentSpanID == spans[p].SpanID {
					spans[p].ChildSpans = append(spans[p].ChildSpans, &spans[c])
				}
			}
			// make order of child spans deterministic
			sort.Slice(spans[p].ChildSpans, func(i, j int) bool {
				return spans[p].ChildSpans[i].Name < spans[p].ChildSpans[j].Name
			})
		}
		ret = append(ret, Trace{Spans: spans})
	}
	if len(ret) > 0 {

// TODO(bianpengyuan) consider using zipkin proto api https://github.com/istio/istio/issues/13926
type Span struct {
	SpanID       string
	ParentSpanID string
	ServiceName  string
	Name         string
	ChildSpans   []*Span
}

// Trace represents a trace by a collection of spans which all belong to that trace
type Trace struct {
	Spans []Span
}

// New returns a new instance of zipkin.