private void DrawStatisticGUI()
        {
            string label = "Statistic";
            string id    = "statistic" + instance.GetInstanceID();

            GEditorCommon.Foldout(label, true, id, () =>
            {
                List <string> keys = instance.GetKeys();
                int geoMeshCount   = 0;
                int grassMeshCount = 0;
                for (int i = 0; i < keys.Count; ++i)
                {
                    if (keys[i].StartsWith(GCommon.CHUNK_MESH_NAME_PREFIX))
                    {
                        geoMeshCount += 1;
                    }
                    else if (keys[i].StartsWith(GCommon.GRASS_MESH_NAME_PREFIX))
                    {
                        grassMeshCount += 1;
                    }
                }

                EditorGUILayout.LabelField("Geometry Mesh", geoMeshCount.ToString());
                EditorGUILayout.LabelField("Grass Mesh", grassMeshCount.ToString());

                string filePath   = AssetDatabase.GetAssetPath(instance);
                FileInfo fileInfo = new FileInfo(filePath);
                if (fileInfo != null)
                {
                    long length = fileInfo.Length;
                    EditorGUILayout.LabelField("Size", string.Format("{0} MB", (length / 1000000).ToString("0.00")));
                }
            });
        }
        private void DrawStatisticGUI()
        {
            string label = "Statistic";
            string id    = "statistic" + instance.GetInstanceID();

            GEditorCommon.Foldout(label, true, id, () =>
            {
                string filePath   = AssetDatabase.GetAssetPath(instance);
                FileInfo fileInfo = new FileInfo(filePath);
                if (fileInfo != null)
                {
                    long length = fileInfo.Length;
                    EditorGUILayout.LabelField("Size", string.Format("{0} MB", (length / 1000000).ToString("0.00")));
                }
            });
        }