feat: add cluster getPeerClient() func

cluster/com.go

@@ -0,0 +1,26 @@
+package cluster
+
+import (
+	"context"
+	"errors"
+	"github.com/stream1080/godis/resp/client"
+)
+
+func (cluster *ClusterDatabases) getPeerClient(peer string) (*client.Client, error) {
+	pool, ok := cluster.peerConn[peer]
+	if !ok {
+		return nil, errors.New("conn not found")
+	}
+
+	object, err := pool.BorrowObject(context.Background())
+	if err != nil {
+		return nil, err
+	}
+
+	c, ok := object.(*client.Client)
+	if !ok {
+		return nil, errors.New("wrong type")
+	}
+
+	return c, nil
+}