Merge pull request #51 from liuyts/master

Add a push function for custom message key

kq/pusher.go

@@ -112,8 +112,13 @@ func (p *Pusher) KPush(ctx context.Context, k, v string) error {
 
 // Push sends a message to the Kafka topic.
 func (p *Pusher) Push(ctx context.Context, v string) error {
+	return p.PushWithKey(ctx, strconv.FormatInt(time.Now().UnixNano(), 10), v)
+}
+
+// PushWithKey sends a message with the given key to the Kafka topic.
+func (p *Pusher) PushWithKey(ctx context.Context, key, v string) error {
 	msg := kafka.Message{
-		Key:   []byte(strconv.FormatInt(time.Now().UnixNano(), 10)), // current timestamp
+		Key:   []byte(key),
 		Value: []byte(v),
 	}