Validate written data in FileStorage

[olegmoz]

It might be a good idea, to validate just written file checksum. It may happen that something went wrong writing the file. For example we had a bug when last few bytes of file were missing, something may go wrong with file sytem, etc

[0crat]

@g4s8/z please, pay attention to this issue

[0crat]

@olegmoz/z this project will fix the problem faster if you donate a few dollars to it; just click here and pay via Stripe, it's very fast, convenient and appreciated; thanks a lot!