diff --git a/utils/sync2/counter_cond.go b/utils/sync2/counter_cond.go
index 8da29e2..03bc8b6 100644
--- a/utils/sync2/counter_cond.go
+++ b/utils/sync2/counter_cond.go
@@ -32,7 +32,9 @@ func (c *CounterCond) Wait() bool {
 }
 
 func (c *CounterCond) Release() {
+	c.cond.L.Lock()
 	c.count++
+	c.cond.L.Unlock()
 	c.cond.Signal()
 }
 
diff --git a/utils/sync2/unbound_channel.go b/utils/sync2/unbound_channel.go
new file mode 100644
index 0000000..ff051a4
--- /dev/null
+++ b/utils/sync2/unbound_channel.go
@@ -0,0 +1,74 @@
+package sync2
+
+import (
+	"container/list"
+	"sync"
+)
+
+type UnboundChannel[T any] struct {
+	values *list.List
+	cond   *sync.Cond
+	err    error
+}
+
+func NewUnboundChannel[T any]() *UnboundChannel[T] {
+	return &UnboundChannel[T]{
+		values: list.New(),
+		cond:   sync.NewCond(&sync.Mutex{}),
+	}
+}
+
+func (c *UnboundChannel[T]) Error() error {
+	return c.err
+}
+
+func (c *UnboundChannel[T]) Send(val T) error {
+	c.cond.L.Lock()
+	if c.err != nil {
+		c.cond.L.Unlock()
+		return c.err
+	}
+	c.values.PushBack(val)
+	c.cond.L.Unlock()
+
+	c.cond.Signal()
+	return nil
+}
+
+func (c *UnboundChannel[T]) Receive() (T, error) {
+	c.cond.L.Lock()
+	defer c.cond.L.Unlock()
+
+	if c.values.Len() == 0 {
+		c.cond.Wait()
+	}
+
+	if c.values.Len() == 0 {
+		var ret T
+		return ret, c.err
+	}
+
+	ret := c.values.Front().Value.(T)
+	c.values.Remove(c.values.Front())
+	return ret, nil
+}
+
+func (c *UnboundChannel[T]) Close() {
+	c.cond.L.Lock()
+	if c.err != nil {
+		return
+	}
+	c.err = ErrChannelClosed
+	c.cond.L.Unlock()
+	c.cond.Broadcast()
+}
+
+func (c *UnboundChannel[T]) CloseWithError(err error) {
+	c.cond.L.Lock()
+	if c.err != nil {
+		return
+	}
+	c.err = err
+	c.cond.L.Unlock()
+	c.cond.Broadcast()
+}
diff --git a/utils/time2/duration.go b/utils/time2/duration.go
new file mode 100644
index 0000000..ebe0425
--- /dev/null
+++ b/utils/time2/duration.go
@@ -0,0 +1,28 @@
+package time2
+
+import (
+	"fmt"
+	"time"
+)
+
+type Duration struct {
+	time.Duration
+}
+
+func (d *Duration) Std() time.Duration {
+	return d.Duration
+}
+
+func (d *Duration) Scan(state fmt.ScanState, verb rune) error {
+	data, err := state.Token(true, nil)
+	if err != nil {
+		return err
+	}
+
+	d.Duration, err = time.ParseDuration(string(data))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
diff --git a/utils/time2/time2_test.go b/utils/time2/time2_test.go
new file mode 100644
index 0000000..2dd0202
--- /dev/null
+++ b/utils/time2/time2_test.go
@@ -0,0 +1,25 @@
+package time2
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func Test_Duration(t *testing.T) {
+	Convey("从字符串解析", t, func() {
+		dur := Duration{}
+		_, err := fmt.Sscanf("10s", "%v", &dur)
+		So(err, ShouldEqual, nil)
+		So(dur.Std(), ShouldEqual, 10*time.Second)
+	})
+
+	Convey("包含空白字符", t, func() {
+		dur := Duration{}
+		_, err := fmt.Sscanf(" 10s\t\n\r", "%v", &dur)
+		So(err, ShouldEqual, nil)
+		So(dur.Std(), ShouldEqual, 10*time.Second)
+	})
+}