dotnet add package Microsoft.SharePoint.Client --version 14.0.4762.1000 dotnet add package PDFsharp --version 6.0.0
https://www.sharepointpals.com/post/upload-file-to-sharepoint-office-365-programmatically-using-c-csom-pnp/ https://learn.microsoft.com/en-us/answers/questions/665350/need-a-console-application-in-c-to-upload-files-to https://learn.microsoft.com/en-us/answers/questions/1344187/download-10-million-files-from-sharepoint-online-c
https://github.com/cwiederspan/pdf-splitter/blob/master/src/Splitter.cs
http://www.pdfsharp.net/wiki/ExportImages-sample.ashx?AspxAutoDetectCookieSupport=1