Function write_xlsx_named 

pub fn write_xlsx_named(
    wb: &Workbook,
    kind: XlsxKind,
    book_name: &str,
) -> Result<Vec<u8>, IoError>

Writes a workbook as the given member of the .xlsx family for the file book_name (a bare file name, used for the workbook in a PivotChart’s link to its PivotTable).