Integrate logging system into Flutter app with service registration and testing setup

finlog_app/fluttery/lib/src/logger/logger_impl.dart

@@ -0,0 +1,57 @@
+import 'package:flutter/material.dart';
+import 'package:fluttery/logger/logger.dart';
+import 'package:logging/logging.dart' as lib;
+
+// ignore_for_file: avoid_print
+class LoggerImpl implements Logger {
+  final lib.Logger _logger;
+
+  // coverage:ignore-start
+  /// Constructor
+  LoggerImpl() : _logger = lib.Logger("Logger") {
+    _logger.onRecord.listen((lib.LogRecord record) {
+      print('${record.level.name}: ${record.time}: ${record.message}');
+      if (record.error != null) {
+        print('Error: ${record.error}');
+      }
+      if (record.stackTrace != null) {
+        print('Stack Trace: ${record.stackTrace}');
+      }
+    });
+  }
+
+  // coverage:ignore-end
+  @visibleForTesting
+  factory LoggerImpl.forTest(lib.Logger logger) {
+    final instance = LoggerImpl._internal(logger);
+    return instance;
+  }
+
+  // Private internal constructor
+  LoggerImpl._internal(this._logger);
+
+  @override
+  void info(String message) {
+    _logger.info(message);
+  }
+
+  @override
+  void warning(String message) {
+    _logger.warning(message);
+  }
+
+  @override
+  void error(String message, [Object? error, StackTrace? stackTrace]) {
+    _logger.severe(message, error, stackTrace);
+  }
+
+  @override
+  void debug(String message) {
+    _logger.fine(message);
+  }
+
+  @override
+  void setLogLevel(lib.Level level) {
+    _logger.level = level;
+  }
+}