//We can read more than we need if the actualCount is not multiple 
        //of the byteBuffer size and file is big enough. In that case we cannot
        //use flip method but we need to set buffer limit manually to trans.
//We can read more than we need if the actualCount is not multiple 
        //of the byteBuffer size and file is big enough. In that case we cannot
        //use flip method but we need to set buffer limit manually to trans. | FadvisedFileRegion.java