diff --git a/event/builder.go b/event/builder.go
index f90804f..a0567e3 100644
--- a/event/builder.go
+++ b/event/builder.go
@@ -259,26 +259,26 @@
 }
 
 // Start delivers a start event with the given name and labels.
-// Its second return value is a function that should be called to deliver the
-// matching end event.
+// Its second return value is a Builder whose End method can be
+// called to deliver the matching End event.
+// (It is also fine to ignore the Builder.)
 // All events created from the returned context will have this start event
 // as their parent.
-func (b Builder) Start(name string) (context.Context, func()) {
+func (b Builder) Start(name string) (context.Context, Builder) {
 	if b.data == nil {
-		return b.ctx, func() {}
+		return b.ctx, Builder{}
 	}
 	checkValid(b.data, b.builderID)
 	ctx := b.ctx
-	end := func() {}
+	var endBuilder Builder
 	if b.data.exporter.tracingEnabled() {
 		b.data.exporter.mu.Lock()
 		defer b.data.exporter.mu.Unlock()
 		b.data.exporter.lastEvent++
 		traceID := b.data.exporter.lastEvent
 		// create the end builder
-		eb := b.Clone()
-		eb.data.Event.Parent = traceID
-
+		endBuilder = b.Clone()
+		endBuilder.data.Event.Parent = traceID
 		b.data.Event.Labels = append(b.data.Event.Labels, Trace.Of(traceID))
 		b.data.exporter.prepare(&b.data.Event)
 		// and now deliver the start event
@@ -286,12 +286,11 @@
 		now := time.Now()
 		ctx = newContext(ctx, b.data.exporter, traceID, now)
 		ctx = b.data.exporter.handler.Start(ctx, &b.data.Event)
-		eb.data.parentStart = now
-		eb.ctx = ctx
-		end = eb.End
+		endBuilder.data.parentStart = now
+		endBuilder.ctx = ctx
 	}
 	b.done()
-	return ctx, end
+	return ctx, endBuilder
 }
 
 func checkValid(b *builder, wantID uint64) {
diff --git a/event/builder_test.go b/event/builder_test.go
index 4f4166c..c7d698f 100644
--- a/event/builder_test.go
+++ b/event/builder_test.go
@@ -68,12 +68,12 @@
 	// Verify that the context returned from the handler is also returned from Start,
 	// and is the context passed to End.
 	ctx := event.WithExporter(context.Background(), event.NewExporter(&testTraceHandler{t: t}, nil))
-	ctx, end := event.To(ctx).Start("s")
+	ctx, eb := event.To(ctx).Start("s")
 	val := ctx.Value("x")
 	if val != 1 {
 		t.Fatal("context not returned from Start")
 	}
-	end()
+	eb.End()
 }
 
 type testTraceHandler struct {
@@ -142,15 +142,15 @@
 		}
 	}
 
-	t.Run("end function", func(t *testing.T) {
+	t.Run("returned builder", func(t *testing.T) {
 		h := &testTraceDurationHandler{}
 		ctx := event.WithExporter(context.Background(), event.NewExporter(h, nil))
-		ctx, end := event.To(ctx).With(event.DurationMetric.Of(dur)).Start("s")
+		ctx, eb := event.To(ctx).With(event.DurationMetric.Of(dur)).Start("s")
 		time.Sleep(want)
-		end()
+		eb.End()
 		check(t, h)
 	})
-	t.Run("End method", func(t *testing.T) {
+	t.Run("separate builder", func(t *testing.T) {
 		h := &testTraceDurationHandler{}
 		ctx := event.WithExporter(context.Background(), event.NewExporter(h, nil))
 		ctx, _ = event.To(ctx).Start("s")
diff --git a/event/common_test.go b/event/common_test.go
index 1fdfbd5..c175dae 100644
--- a/event/common_test.go
+++ b/event/common_test.go
@@ -35,12 +35,12 @@
 	checkFind(t, h, "Annotate", event.Name, false, "")
 	h.Reset()
 
-	_, end := event.To(ctx).Start(trace)
+	_, eb := event.To(ctx).Start(trace)
 	checkFind(t, h, "Start", event.Message, false, "")
 	checkFind(t, h, "Start", event.Name, true, trace)
 	h.Reset()
 
-	end()
+	eb.End()
 	checkFind(t, h, "End", event.Message, false, "")
 	checkFind(t, h, "End", event.Name, false, "")
 }
diff --git a/event/event_test.go b/event/event_test.go
index 4a01b72..d2321bb 100644
--- a/event/event_test.go
+++ b/event/event_test.go
@@ -53,8 +53,8 @@
 	}, {
 		name: "span",
 		events: func(ctx context.Context) {
-			ctx, end := event.To(ctx).Start("span")
-			end()
+			ctx, eb := event.To(ctx).Start("span")
+			eb.End()
 		},
 		expect: `
 time=2020-03-05T14:27:48 trace=1 name=span
@@ -62,10 +62,10 @@
 `}, {
 		name: "span nested",
 		events: func(ctx context.Context) {
-			ctx, end := event.To(ctx).Start("parent")
-			defer end()
-			child, end2 := event.To(ctx).Start("child")
-			defer end2()
+			ctx, eb := event.To(ctx).Start("parent")
+			defer eb.End()
+			child, eb2 := event.To(ctx).Start("child")
+			defer eb2.End()
 			event.To(child).Log("message")
 		},
 		expect: `
diff --git a/event/otel/trace_test.go b/event/otel/trace_test.go
index fe05ef0..c29f392 100644
--- a/event/otel/trace_test.go
+++ b/event/otel/trace_test.go
@@ -95,9 +95,9 @@
 		ctx, span = s.tracer.Start(ctx, s.name)
 		defer span.End()
 	} else {
-		var end func()
-		ctx, end = event.To(ctx).Start(s.name)
-		defer end()
+		var eb event.Builder
+		ctx, eb = event.To(ctx).Start(s.name)
+		defer eb.End()
 	}
 	for _, c := range s.children {
 		c.apply(ctx)