Allow FileLifecycleHooks to change the length of the stream

[augustoproiete]

Currently files are opened with FileMode.Append, which prevents FileLifecycleHooks from modifying the size of the stream when implementing an OnFileOpened hook.

In addition, when fileSizeLimitBytes is set, the stream is wrapped via WriteCountingStream which does not implement SetLength.

Changing the size of the stream can be useful in a few scenarios, such as:

• Creating a new log file every time the app runs (i.e. truncate instead of append)
• Set an initial size to pre-allocate/reserve disk space for the log file (e.g. 1 GB)

---

• Calling SetLength with fileSizeLimitBytes to null throws System.IO.IOException: Unable to truncate data that previously existed in a file opened in Append mode

• Calling SetLength with fileSizeLimitBytes to any number throws System.NotSupportedException: Specified method is not supported