Does FileStream.Dispose close the file immediately?

I have some code that writes a file by saving a MemoryStream to a FileStream using MemoryStream.WriteTo(). After the file is closed it is opened up again to read some metdata...

This works about 80 - 90% of the time. The other 20% I get an exception saying the file is "in use by another process".

Does FileStream.Dispose() not release resources synchronously? Is there something going on lower in Win32 land I'm not aware of? I'm not seeing anything obvious in the .Net documentation.

As "immediately" as possible. There can easily be some lag due to outstanding writes, delay in updating the directory info etc. It could also be anti-virus software checking your changed file.

This may be a rare case where a Thread.Sleep(1) is called for. But to be totally safe you will have to catch the (any) exception and try again a set number of times.