writeBuffer doesn't return Buffer type

Thanks for the great package. I'm using exceljs with Typescript, but writeBuffer() function returns ExcelJS.Buffer instead of Buffer type. And since ExcelJS.Buffer inherits from ArrayBuffer, converting ArrayBuffer to Buffer will break excel file. Does anyone have a solution to this problem? Thanks in advance!

declare interface Buffer extends ArrayBuffer { }

let resultExcel: Buffer; // buffer
const tmpResultExcel: ExcelJS.Buffer = await tmpWorkBook.xlsx.writeBuffer(); // arraybuffer
resultExcel = Buffer.from(tmpResultExcel); // doesn't work well