title: How to detect block level changes in a file in C#?
body: <p>How I may know which file is modified and what data is changed in the file?</p>
  
  <p>Edit: I want to watch the file as it gets modified and then compare it against a previous version to know which data blocks are changed. I guess watching the file for changes can be accomplished by using file watcher API but I have no idea about the second part.</p>