anchor.diff:  
       Logger.root.level = logLevel;
   
  -    logListener = Logger.root.onRecord.listen(environment.onLog);
  +    var logListener = Logger.root.onRecord.listen(environment.onLog);
   
       /// Set up other defaults.
       debounceDelay ??= const Duration(milliseconds: 250);
  
positive.code:   // For testing only, skips the build script updates check.
    bool skipBuildScriptCheck;
  
    BuildOptions(BuildEnvironment environment,
        {@required this.packageGraph,
        BuildConfig rootPackageConfig,
        this.debounceDelay,
        this.deleteFilesByDefault,
        this.failOnSevere,
        Level logLevel,
        this.skipBuildScriptCheck,
        this.enableLowResourcesMode,
        this.outputDir,
        this.trackPerformance,
        this.verbose}) {
      // Set up logging
      verbose ??= false;
      logLevel ??= verbose ? Level.ALL : Level.INFO;
  
negative.code: // BSD-style license that can be found in the LICENSE file.
  
  import 'dart:async';
  import 'dart:collection';
  
  import 'package:build_config/build_config.dart';
  import 'package:logging/logging.dart';
  