Move unix specific logic into _unix.go

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/container_stats_list_windows.go

@@ -0,0 +1,35 @@
+// +build windows
+
+/*
+Copyright The containerd Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package server
+
+import (
+	"github.com/containerd/containerd/api/types"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1alpha2"
+
+	containerstore "github.com/containerd/cri/pkg/store/container"
+)
+
+// TODO(windows): Implement a dummy version of this, and actually support this
+// when stats is supported by the hcs containerd shim.
+func (c *criService) containerMetrics(
+	meta containerstore.Metadata,
+	stats *types.Metric,
+) (*runtime.ContainerStats, error) {
+	return nil, nil
+}