QFileSystemWatcher::fileChanged() on Windows doesn't trigger on flush()

I am using the QFileSystemWatcher to trace changes on files. Such files can be opened by another application which is appending a new data to them. The application flushes file stream after each append operation. File is only closed when application closes. It can't be closed after each entry, because it could harmfully impact on performance.
The problem is that the signal QFileSystemWatcher::fileChanged() is only emitted when:

• file is closed;
• file is opened by another application (an example is refreshing directory containing that file in file explorator).

Such problem doesn't occur on Unix-based systems. What is more the behavior I am expecting is intentional, as stated in comment:
https://bugreports.qt-project.org/browse/QTBUG-8244?focusedCommentId=108330&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-108330

Exploring Qt source code brings conclusion that QFileSystemWatcher is using last modification time as changing criterion and problem probably lies in different implementation of updating that time on Windows system. Is it possible to use additional criterion (like size of file) or use some system-specific functions ( http://msdn.microsoft.com/en-us/library/aa365465(VS.85).aspx , http://msdn.microsoft.com/en-us/library/aa364417(v=vs.85).aspx ) ?

src\corelib\io\qfilesystemwatcher_win.cpp:401