Fix analyze issues

Author: JSUYA

packages/tizen_package_manager/example/lib/main.dart

@@ -80,7 +80,7 @@ class _CurrentPackageScreenState extends State<_CurrentPackageScreen> {
   @override
   Widget build(BuildContext context) {
     return FutureBuilder<List<dynamic>>(
-      future: Future.wait([
+      future: Future.wait(<Future<dynamic>>[
         PackageManager.getPackageInfo(currentPackageId),
         PackageManager.getPackageSizeInfo(currentPackageId),
       ]),
@@ -147,7 +147,8 @@ class _PackageListScreenState extends State<_PackageListScreen>
             await PackageManager.getPackageSizeInfo(package.packageId);
         sizeInfoMap[package.packageId] = sizeInfo;
       } catch (e) {
-        print('Failed to get size info for package ${package.packageId}: $e');
+        debugPrint(
+            'Failed to get size info for package ${package.packageId}: $e');
       }
     }
 
@@ -194,7 +195,7 @@ class _PackageListScreenState extends State<_PackageListScreen>
                           '${sizeInfo != null ? '\nApp Size: ${sizeInfo.appSize} bytes' : ''}',
                         ),
                       ),
-                      isThreeLine: sizeInfo != null ? true : false,
+                      isThreeLine: sizeInfo != null,
                     );
                   },
                 );

packages/tizen_package_manager/lib/tizen_package_manager.dart

@@ -115,6 +115,7 @@ class PackageManager {
     return list;
   }
 
+  /// Gets the package size information for the given package ID.
   static Future<PackageSizeInfo> getPackageSizeInfo(String packageId) async {
     if (packageId.isEmpty) {
       throw ArgumentError('Must not be empty', 'packageId');
@@ -242,6 +243,7 @@ class PackageInfo {
   }
 }
 
+/// Represents size information of specific package.
 class PackageSizeInfo {
   /// Creates an instance of [PackageInfo] with the given parameters.
   PackageSizeInfo({