OptionalchunkRows asked for per request while fetching for the 'all' and
'selected' scopes.
OptionalfileFile name, with or without the .csv suffix.
OptionalmaxMost rows fetched for the 'all' and 'selected' scopes. The server is
never asked for rows past this. Raise it deliberately: every row is held
in memory to build the file.
OptionalonlyExport only the selected rows.
OptionalscopeWhich rows to export. See ExportScope.
OptionalseparatorField separator.
Options for GridApi.exportCsv.