anchor.diff:  }
   
   class _ServerSocket {
  -  factory ServerSocket(String bindAddress, int port, int backlog) {
  +  factory _ServerSocket(String bindAddress, int port, int backlog) {
       throw new UnsupportedOperationException(
           'new ServerSocket($bindAddress, $port, $backlog)');
     }
   }
   
   class _Socket {
  -  factory Socket(String host, int port) {
  +  factory _Socket(String host, int port) {
       throw new UnsupportedOperationException('new Socket($host, $port)');
     }
   }
  
positive.code: }
  
  class _Directory {
    factory Directory(arg) {
      throw new UnsupportedOperationException('new Directory($arg)');
    }
  
    factory Directory.fromPath(arg) {
      throw new UnsupportedOperationException('new Directory.fromPath($arg)');
    }
  
    factory Directory.current() {
      throw new UnsupportedOperationException('new Directory.current()');
    }
  }
  
negative.code: }
  
  class _File {
    factory _File(arg) {
      throw new UnsupportedOperationException('new File($arg)');
    }
  
    factory _File.fromPath(arg) {
      throw new UnsupportedOperationException('new File.fromPath($arg)');
    }
  }
  