The filename for the exported serialization data if the
The filename extension for JSON will be automatically added.
It can be an absolute path or file URL or a relative path.
If some relative path is chosen it will be created in a temporary system
directory and overwritten if the corresponding file already exists.
If the value is
null an new temporary file will be
created for every export based on the filename for the exported image or
// Defaults to: null
final String filename;