anchor.diff:    openedFile.writeByte(0);
     openedFile.onError = (e) {
       checkWriteReadOnlyFileException(e);
  -    p.toSendPort().send(null);
  +    openedFile.close(() => p.toSendPort().send(null));
     };
   }
   
  
positive.code: 
    var file = new File("${temp.path}/test_file");
    file.createSync();
    var openedFile = file.openSync(FileMode.READ);
  
    // Truncating read only file should throw an exception.
    Expect.throws(() => openedFile.truncateSync(0),
  
negative.code:   openedFile.truncate(0, () => Expect.fail("Unreachable code"));
    openedFile.onError = (e) {
      checkWriteReadOnlyFileException(e);
      openedFile.close(() => p.toSendPort().send(null));
    };
  }
  
  