[#XX] rpc: Introduce ObjectService.Patch method

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

rpc/object.go

@@ -18,6 +18,7 @@ const (
 	rpcObjectHead      = "Head"
 	rpcObjectDelete    = "Delete"
 	rpcObjectPutSingle = "PutSingle"
+	rpcObjectPatch     = "Patch"
 )
 
 // PutRequestWriter is an object.PutRequest
@@ -205,3 +206,38 @@ func PutSingleObject(
 
 	return resp, nil
 }
+
+// PatchRequestWriter is an object.PatchRequest
+// message streaming component.
+type PatchRequestWriter struct {
+	wc client.MessageWriterCloser
+
+	resp message.Message
+}
+
+// Write writes req to the stream.
+func (w *PatchRequestWriter) Write(req *object.PatchRequest) error {
+	return w.wc.WriteMessage(req)
+}
+
+// Close closes the stream.
+func (w *PatchRequestWriter) Close() error {
+	return w.wc.Close()
+}
+
+// Patch executes ObjectService.Patch RPC.
+func Patch(
+	cli *client.Client,
+	resp *object.PatchResponse,
+	opts ...client.CallOption,
+) (*PatchRequestWriter, error) {
+	wc, err := client.OpenClientStream(cli, common.CallMethodInfoClientStream(serviceObject, rpcObjectPatch), resp, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &PatchRequestWriter{
+		wc:   wc,
+		resp: resp,
+	}, nil
+}