mark dubbo2 rpc protocol implementation deprecated
diff --git a/hessian.go b/hessian.go
index 0549984..231dbea 100644
--- a/hessian.go
+++ b/hessian.go
@@ -15,6 +15,10 @@
* limitations under the License.
*/
+// This file contains the implementation of
+// [dubbo2 rpc protocol](https://dubbo.apache.org/zh/docs/concepts/rpc-protocol/#dubbo2), which is deprecated.
+// Use the [implementation](https://github.com/apache/dubbo-go/tree/master/protocol/dubbo/hessian2) in dubbo-go project instead.
+
package hessian
import (
diff --git a/request.go b/request.go
index 7a50465..a6def73 100644
--- a/request.go
+++ b/request.go
@@ -15,6 +15,10 @@
* limitations under the License.
*/
+// This file contains the implementation of
+// [dubbo2 rpc protocol](https://dubbo.apache.org/zh/docs/concepts/rpc-protocol/#dubbo2), which is deprecated.
+// Use the [implementation](https://github.com/apache/dubbo-go/tree/master/protocol/dubbo/hessian2) in dubbo-go project instead.
+
package hessian
import (
diff --git a/response.go b/response.go
index 66235d7..5f90592 100644
--- a/response.go
+++ b/response.go
@@ -15,6 +15,10 @@
* limitations under the License.
*/
+// This file contains the implementation of
+// [dubbo2 rpc protocol](https://dubbo.apache.org/zh/docs/concepts/rpc-protocol/#dubbo2), which is deprecated.
+// Use the [implementation](https://github.com/apache/dubbo-go/tree/master/protocol/dubbo/hessian2) in dubbo-go project instead.
+
package hessian
import (
