add getter for grpc_client

Author: Pulkit0110

google/cloud/storage/_experimental/grpc_client.py

@@ -106,3 +106,17 @@ def _create_gapic_client(
             client_info=client_info,
             client_options=client_options,
         )
+
+    @property
+    def grpc_client(self):
+        """The underlying gRPC client.
+
+        This property gives users direct access to the `storage_v2.StorageClient`
+         instance. This can be useful for accessing
+        newly added or experimental RPCs that are not yet exposed through
+        the high-level GrpcClient.
+
+        Returns:
+            google.cloud.storage_v2.StorageClient: The configured GAPIC client.
+        """
+        return self._grpc_client

tests/unit/test_grpc_client.py

@@ -107,3 +107,18 @@ def test_constructor_handles_api_key(self, mock_storage_client, mock_base_client
         # that contains the api_key.
         _, kwargs = mock_storage_client.call_args
         self.assertEqual(kwargs["client_options"]["api_key"], "test-api-key")
+
+    @mock.patch("google.cloud.storage._experimental.grpc_client.ClientWithProject")
+    @mock.patch("google.cloud._storage_v2.StorageClient")
+    def test_grpc_client_property(self, mock_storage_client, mock_base_client):
+        from google.cloud.storage._experimental import grpc_client
+
+        mock_creds = mock.Mock(spec=auth_credentials.Credentials)
+        mock_base_instance = mock_base_client.return_value
+        mock_base_instance._credentials = mock_creds
+
+        client = grpc_client.GrpcClient(project="test-project", credentials=mock_creds)
+
+        retrieved_client = client.grpc_client
+
+        self.assertIs(retrieved_client, mock_storage_client.return_value)