Opens the vault's root data stream.
This method opens the vault's root data stream, returning a stream object that provides access to its data.
Please refer to the Using RootData topic for more information.
Note: This method can only be called when Active is true, and cannot be called within events.
This method returns a Stream; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.