diff --git a/empty.go b/empty.go
index fa766817..66302ba8 100644
--- a/empty.go
+++ b/empty.go
@@ -3,7 +3,6 @@ package rx
 import (
 	"context"
 
-	"github.com/b97tsk/rx/internal/ctxwatch"
 	"github.com/b97tsk/rx/internal/waitgroup"
 )
 
@@ -30,7 +29,7 @@ func never[T any](ctx context.Context, sink Observer[T]) {
 			wg.Add(1)
 		}
 
-		ctxwatch.Add(ctx, func() {
+		context.AfterFunc(ctx, func() {
 			if wg != nil {
 				defer wg.Done()
 			}
diff --git a/go.mod b/go.mod
index dd158340..f2a1c2d4 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/b97tsk/rx
 
-go 1.19
+go 1.21.0
 
 require golang.org/x/exp v0.0.0-20220428152302-39d4317da171
 
diff --git a/internal/ctxwatch/ctxwatch.go b/internal/ctxwatch/ctxwatch.go
deleted file mode 100644
index 5f585c9b..00000000
--- a/internal/ctxwatch/ctxwatch.go
+++ /dev/null
@@ -1,198 +0,0 @@
-package ctxwatch
-
-import (
-	"context"
-	"reflect"
-	"sync"
-	"sync/atomic"
-
-	"github.com/b97tsk/rx/internal/queue"
-)
-
-type watchItem struct {
-	Context  context.Context
-	Callback func()
-}
-
-type watchService chan<- watchItem
-
-func startService() watchService {
-	cin, cout := make(chan watchItem), make(chan watchItem)
-
-	go func() {
-		var q queue.Queue[watchItem]
-
-		for {
-			var (
-				in   <-chan watchItem = cin
-				out  chan<- watchItem
-				outv watchItem
-			)
-
-			if q.Len() > 0 {
-				out, outv = cout, q.Front()
-			}
-
-			select {
-			case item := <-in:
-				q.Push(item)
-			case out <- outv:
-				q.Pop()
-			}
-		}
-	}()
-
-	go func() {
-		cases := []reflect.SelectCase{{}}
-
-		var itemCounter atomic.Int32
-
-		var (
-			workloadDoneChans sync.Map
-			workloadPerWorker atomic.Int32
-		)
-
-		oldWorkloadPerWorker := 3
-
-		workloadPerWorker.Store(5)
-
-		for item := range cout {
-			itemValue := reflect.ValueOf(item)
-
-			for i, j := 1, len(cases); i < j; i++ {
-				cases[i].Send = itemValue
-			}
-
-			dir0 := reflect.SelectSend
-			if n := len(cases); int(itemCounter.Load()) >= (n-1)*oldWorkloadPerWorker {
-				dir0 = reflect.SelectDefault
-			}
-
-			cases[0].Dir = dir0
-
-			itemCounter.Add(1)
-
-			for {
-				if i, _, _ := reflect.Select(cases); i > 0 {
-					break
-				}
-
-				cases[0].Dir = reflect.SelectSend
-
-				worker := make(chan watchItem)
-				workerValue := reflect.ValueOf(worker)
-
-				cases = append(cases, reflect.SelectCase{
-					Dir:  reflect.SelectSend,
-					Chan: workerValue,
-					Send: itemValue,
-				})
-
-				w := workloadPerWorker.Load()
-				w2 := w + int32(oldWorkloadPerWorker)
-				oldWorkloadPerWorker = int(w)
-
-				workloadDoneChans.Store(w2, make(chan struct{}))
-				workloadPerWorker.Store(w2)
-
-				if done, loaded := workloadDoneChans.LoadAndDelete(w); loaded {
-					close(done.(chan struct{}))
-				}
-
-				go startWorker(workerValue, &itemCounter, &workloadDoneChans, &workloadPerWorker)
-			}
-
-			for i, j := 1, len(cases); i < j; i++ {
-				cases[i].Send = reflect.Value{}
-			}
-		}
-	}()
-
-	return cin
-}
-
-func startWorker(
-	workerChan reflect.Value,
-	itemCounter *atomic.Int32,
-	workloadDoneChans *sync.Map,
-	workloadPerWorker *atomic.Int32,
-) {
-	cases := []reflect.SelectCase{{Dir: reflect.SelectRecv}}
-	items := []watchItem{{}}
-
-	for {
-		chan0 := workerChan
-
-		if w := workloadPerWorker.Load(); int(w) < len(items) {
-			done, ok := workloadDoneChans.Load(w)
-			if !ok { // workloadPerWorker has just changed.
-				continue
-			}
-
-			chan0 = reflect.ValueOf(done)
-		}
-
-		cases[0].Chan = chan0
-
-		switch i, v, _ := reflect.Select(cases); i {
-		case 0:
-			item, ok := v.Interface().(watchItem)
-			if !ok {
-				break
-			}
-
-			cases = append(cases, reflect.SelectCase{
-				Dir:  reflect.SelectRecv,
-				Chan: reflect.ValueOf(item.Context.Done()),
-			})
-
-			items = append(items, item)
-		default:
-			j := len(cases) - 1
-			item := items[i]
-
-			cases[i].Chan = cases[j].Chan
-			cases[j].Chan = reflect.Value{}
-			cases = cases[:j]
-
-			items[i] = items[j]
-			items[j] = watchItem{}
-			items = items[:j]
-
-			go item.Callback()
-
-			itemCounter.Add(-1)
-		}
-	}
-}
-
-var shared struct {
-	sync.Once
-	service watchService
-}
-
-func sharedInit() {
-	shared.service = startService()
-}
-
-func getService() watchService {
-	shared.Do(sharedInit)
-	return shared.service
-}
-
-// Add starts a background service that it waits until ctx has been cancelled,
-// then it calls f in a goroutine. Subsequent calls use the same service to
-// deal with arbitrary number of context.Contexts.
-//
-// Add works just like:
-//
-//	go func() {
-//		<-ctx.Done()
-//		f()
-//	}()
-//
-// except it need not spawn new goroutines for each ctx to wait at the time
-// when Add is called.
-func Add(ctx context.Context, f func()) {
-	getService() <- watchItem{ctx, f}
-}
diff --git a/internal/ctxwatch/ctxwatch_test.go b/internal/ctxwatch/ctxwatch_test.go
deleted file mode 100644
index 90a3e230..00000000
--- a/internal/ctxwatch/ctxwatch_test.go
+++ /dev/null
@@ -1,50 +0,0 @@
-package ctxwatch_test
-
-import (
-	"context"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/b97tsk/rx/internal/ctxwatch"
-)
-
-func TestAdd(t *testing.T) {
-	t.Parallel()
-
-	var v atomic.Int32
-
-	cancels := []context.CancelFunc(nil)
-	done := func() { v.Add(-1) }
-	add := func(n int) {
-		v.Add(int32(n))
-
-		for i := 0; i < n; i++ {
-			ctx, cancel := context.WithCancel(context.Background())
-			cancels = append(cancels, cancel)
-
-			ctxwatch.Add(ctx, done)
-
-			time.Sleep(30 * time.Millisecond)
-		}
-	}
-
-	remove := func(n int) {
-		for _, cancel := range cancels[:n] {
-			cancel()
-		}
-
-		cancels = cancels[n:]
-
-		time.Sleep(30 * time.Millisecond * time.Duration(n))
-	}
-
-	for n, m := 10, 50; n < m; n += 10 {
-		add(m - n)
-		remove(n)
-	}
-
-	if v.Load() != 0 {
-		t.Fail()
-	}
-}
diff --git a/multicast.go b/multicast.go
index 45732876..b424a7af 100644
--- a/multicast.go
+++ b/multicast.go
@@ -5,7 +5,6 @@ import (
 	"runtime"
 	"sync"
 
-	"github.com/b97tsk/rx/internal/ctxwatch"
 	"github.com/b97tsk/rx/internal/waitgroup"
 )
 
@@ -102,7 +101,7 @@ func (m *multicast[T]) subscribe(ctx context.Context, sink Observer[T]) {
 			wg.Add(1)
 		}
 
-		ctxwatch.Add(ctx, func() {
+		context.AfterFunc(ctx, func() {
 			if wg != nil {
 				defer wg.Done()
 			}
diff --git a/multicastreplay.go b/multicastreplay.go
index 570ef15c..957e7cfc 100644
--- a/multicastreplay.go
+++ b/multicastreplay.go
@@ -6,7 +6,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/b97tsk/rx/internal/ctxwatch"
 	"github.com/b97tsk/rx/internal/queue"
 	"github.com/b97tsk/rx/internal/waitgroup"
 )
@@ -180,7 +179,7 @@ func (m *multicastReplay[T]) subscribe(ctx context.Context, sink Observer[T]) {
 			wg.Add(1)
 		}
 
-		ctxwatch.Add(ctx, func() {
+		context.AfterFunc(ctx, func() {
 			if wg != nil {
 				defer wg.Done()
 			}
diff --git a/share.go b/share.go
index b9d20dc2..6cddf3b8 100644
--- a/share.go
+++ b/share.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"sync"
 
-	"github.com/b97tsk/rx/internal/ctxwatch"
 	"github.com/b97tsk/rx/internal/waitgroup"
 )
 
@@ -137,7 +136,7 @@ func (obs *shareObservable[T]) Subscribe(ctx context.Context, sink Observer[T])
 		wg.Add(1)
 	}
 
-	ctxwatch.Add(ctx, func() {
+	context.AfterFunc(ctx, func() {
 		if wg != nil {
 			defer wg.Done()
 		}