diff --git a/acceptor_windows.go b/acceptor_windows.go
index ce6005c0e..d9d6339cd 100644
--- a/acceptor_windows.go
+++ b/acceptor_windows.go
@@ -39,11 +39,7 @@ func (eng *engine) listenStream(ln net.Listener) (err error) {
 			if atomic.LoadInt32(&eng.beingShutdown) == 0 {
 				eng.opts.Logger.Errorf("Accept() fails due to error: %v", err)
 			} else if errors.Is(err, net.ErrClosed) {
-				err = errorx.ErrEngineShutdown
-				// TODO: errors.Join() is not supported until Go 1.20,
-				// 	we will uncomment this line after we bump up the
-				// 	minimal supported go version to 1.20.
-				// err = errors.Join(err, errorx.ErrEngineShutdown)
+				err = errors.Join(err, errorx.ErrEngineShutdown)
 			}
 			return
 		}
@@ -81,9 +77,7 @@ func (eng *engine) ListenUDP(pc net.PacketConn) (err error) {
 			if atomic.LoadInt32(&eng.beingShutdown) == 0 {
 				eng.opts.Logger.Errorf("failed to receive data from UDP fd due to error:%v", err)
 			} else if errors.Is(err, net.ErrClosed) {
-				err = errorx.ErrEngineShutdown
-				// TODO: ditto.
-				// err = errors.Join(err, errorx.ErrEngineShutdown)
+				err = errors.Join(err, errorx.ErrEngineShutdown)
 			}
 			return
 		}
diff --git a/engine_unix.go b/engine_unix.go
index 83a1ae864..3bc488f95 100644
--- a/engine_unix.go
+++ b/engine_unix.go
@@ -19,6 +19,7 @@ package gnet
 
 import (
 	"context"
+	"errors"
 	"runtime"
 	"strings"
 	"sync"
@@ -29,7 +30,7 @@ import (
 	"github.com/panjf2000/gnet/v2/internal/gfd"
 	"github.com/panjf2000/gnet/v2/internal/netpoll"
 	"github.com/panjf2000/gnet/v2/internal/queue"
-	"github.com/panjf2000/gnet/v2/pkg/errors"
+	errorx "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
 )
 
@@ -59,7 +60,7 @@ func (eng *engine) isInShutdown() bool {
 
 // shutdown signals the engine to shut down.
 func (eng *engine) shutdown(err error) {
-	if err != nil && err != errors.ErrEngineShutdown {
+	if err != nil && !errors.Is(err, errorx.ErrEngineShutdown) {
 		eng.opts.Logger.Errorf("engine is being shutdown with error: %v", err)
 	}
 
@@ -211,14 +212,14 @@ func (eng *engine) stop(s Engine) {
 
 	// Notify all event-loops to exit.
 	eng.eventLoops.iterate(func(i int, el *eventloop) bool {
-		err := el.poller.Trigger(queue.HighPriority, func(_ interface{}) error { return errors.ErrEngineShutdown }, nil)
+		err := el.poller.Trigger(queue.HighPriority, func(_ interface{}) error { return errorx.ErrEngineShutdown }, nil)
 		if err != nil {
 			eng.opts.Logger.Errorf("failed to enqueue shutdown signal of high-priority for event-loop(%d): %v", i, err)
 		}
 		return true
 	})
 	if eng.ingress != nil {
-		err := eng.ingress.poller.Trigger(queue.HighPriority, func(_ interface{}) error { return errors.ErrEngineShutdown }, nil)
+		err := eng.ingress.poller.Trigger(queue.HighPriority, func(_ interface{}) error { return errorx.ErrEngineShutdown }, nil)
 		if err != nil {
 			eng.opts.Logger.Errorf("failed to enqueue shutdown signal of high-priority for main event-loop: %v", err)
 		}
diff --git a/internal/netpoll/poller_epoll_default.go b/internal/netpoll/poller_epoll_default.go
index d5e4d4e48..ec47d0b46 100644
--- a/internal/netpoll/poller_epoll_default.go
+++ b/internal/netpoll/poller_epoll_default.go
@@ -19,6 +19,7 @@
 package netpoll
 
 import (
+	"errors"
 	"os"
 	"runtime"
 	"sync/atomic"
@@ -27,7 +28,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/panjf2000/gnet/v2/internal/queue"
-	"github.com/panjf2000/gnet/v2/pkg/errors"
+	errorx "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
 )
 
@@ -133,12 +134,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 			if fd := int(ev.Fd); fd == p.efd { // poller is awakened to run tasks in queues.
 				doChores = true
 			} else {
-				switch err = callback(fd, ev.Events, 0); err {
-				case nil:
-				case errors.ErrAcceptSocket, errors.ErrEngineShutdown:
+				err = callback(fd, ev.Events, 0)
+				if errors.Is(err, errorx.ErrAcceptSocket) || errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in event-loop: %v", err)
 				}
 			}
 		}
@@ -147,12 +145,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 			doChores = false
 			task := p.urgentAsyncTaskQueue.Dequeue()
 			for ; task != nil; task = p.urgentAsyncTaskQueue.Dequeue() {
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
@@ -160,12 +155,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 				if task = p.asyncTaskQueue.Dequeue(); task == nil {
 					break
 				}
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
diff --git a/internal/netpoll/poller_epoll_ultimate.go b/internal/netpoll/poller_epoll_ultimate.go
index fec70097e..730e0485b 100644
--- a/internal/netpoll/poller_epoll_ultimate.go
+++ b/internal/netpoll/poller_epoll_ultimate.go
@@ -18,6 +18,7 @@
 package netpoll
 
 import (
+	"errors"
 	"os"
 	"runtime"
 	"sync/atomic"
@@ -26,7 +27,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/panjf2000/gnet/v2/internal/queue"
-	"github.com/panjf2000/gnet/v2/pkg/errors"
+	errorx "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
 )
 
@@ -135,12 +136,9 @@ func (p *Poller) Polling() error {
 			if pollAttachment.FD == p.epa.FD { // poller is awakened to run tasks in queues.
 				doChores = true
 			} else {
-				switch err = pollAttachment.Callback(pollAttachment.FD, ev.events, 0); err {
-				case nil:
-				case errors.ErrAcceptSocket, errors.ErrEngineShutdown:
+				err = pollAttachment.Callback(pollAttachment.FD, ev.events, 0)
+				if errors.Is(err, errorx.ErrAcceptSocket) || errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in event-loop: %v", err)
 				}
 			}
 		}
@@ -149,12 +147,9 @@ func (p *Poller) Polling() error {
 			doChores = false
 			task := p.urgentAsyncTaskQueue.Dequeue()
 			for ; task != nil; task = p.urgentAsyncTaskQueue.Dequeue() {
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
@@ -162,12 +157,9 @@ func (p *Poller) Polling() error {
 				if task = p.asyncTaskQueue.Dequeue(); task == nil {
 					break
 				}
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
diff --git a/internal/netpoll/poller_kqueue_default.go b/internal/netpoll/poller_kqueue_default.go
index c44be9027..4fbcd8e60 100644
--- a/internal/netpoll/poller_kqueue_default.go
+++ b/internal/netpoll/poller_kqueue_default.go
@@ -19,6 +19,7 @@
 package netpoll
 
 import (
+	"errors"
 	"os"
 	"runtime"
 	"sync/atomic"
@@ -26,7 +27,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/panjf2000/gnet/v2/internal/queue"
-	"github.com/panjf2000/gnet/v2/pkg/errors"
+	errorx "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
 )
 
@@ -118,12 +119,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 				doChores = true
 				p.drainWakeupEvent()
 			} else {
-				switch err = callback(fd, ev.Filter, ev.Flags); err {
-				case nil:
-				case errors.ErrAcceptSocket, errors.ErrEngineShutdown:
+				err = callback(fd, ev.Filter, ev.Flags)
+				if errors.Is(err, errorx.ErrAcceptSocket) || errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in event-loop: %v", err)
 				}
 			}
 		}
@@ -132,12 +130,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 			doChores = false
 			task := p.urgentAsyncTaskQueue.Dequeue()
 			for ; task != nil; task = p.urgentAsyncTaskQueue.Dequeue() {
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
@@ -145,12 +140,9 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 				if task = p.asyncTaskQueue.Dequeue(); task == nil {
 					break
 				}
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
diff --git a/internal/netpoll/poller_kqueue_ultimate.go b/internal/netpoll/poller_kqueue_ultimate.go
index fc50c6521..e12caf0c1 100644
--- a/internal/netpoll/poller_kqueue_ultimate.go
+++ b/internal/netpoll/poller_kqueue_ultimate.go
@@ -19,6 +19,7 @@
 package netpoll
 
 import (
+	"errors"
 	"os"
 	"runtime"
 	"sync/atomic"
@@ -27,7 +28,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/panjf2000/gnet/v2/internal/queue"
-	"github.com/panjf2000/gnet/v2/pkg/errors"
+	errorx "github.com/panjf2000/gnet/v2/pkg/errors"
 	"github.com/panjf2000/gnet/v2/pkg/logging"
 )
 
@@ -120,12 +121,9 @@ func (p *Poller) Polling() error {
 				p.drainWakeupEvent()
 			} else {
 				pollAttachment := restorePollAttachment(unsafe.Pointer(&ev.Udata))
-				switch err = pollAttachment.Callback(int(ev.Ident), ev.Filter, ev.Flags); err {
-				case nil:
-				case errors.ErrAcceptSocket, errors.ErrEngineShutdown:
+				err = pollAttachment.Callback(int(ev.Ident), ev.Filter, ev.Flags)
+				if errors.Is(err, errorx.ErrAcceptSocket) || errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in event-loop: %v", err)
 				}
 			}
 		}
@@ -134,12 +132,9 @@ func (p *Poller) Polling() error {
 			doChores = false
 			task := p.urgentAsyncTaskQueue.Dequeue()
 			for ; task != nil; task = p.urgentAsyncTaskQueue.Dequeue() {
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}
@@ -147,12 +142,9 @@ func (p *Poller) Polling() error {
 				if task = p.asyncTaskQueue.Dequeue(); task == nil {
 					break
 				}
-				switch err = task.Run(task.Arg); err {
-				case nil:
-				case errors.ErrEngineShutdown:
+				err = task.Run(task.Arg)
+				if errors.Is(err, errorx.ErrEngineShutdown) {
 					return err
-				default:
-					logging.Warnf("error occurs in user-defined function, %v", err)
 				}
 				queue.PutTask(task)
 			}