We are planing to migrate a portal from one platform(A) to another(B) and for this, a utility is provided by the vendor to generate XML for A which will be used by us to migrate to B.

Now this utility has a bug that after generating the relevant XML, it doesn't terminate, rather it keeps on appending static junk nodes to it.

For this purpose, I am writing a C# utility to terminate the application when the XML starts getting junk nodes.

Can I access the file which is already being written as below and be assured that it won't error out

```
var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite); 

```

Also, just to confirm, when a file is being written, the new content is appended to already existing file and it does not first flushes out everything and then write the updated content.(I'm almost sure that I am right on this).