saveAs static method
"Save as" dialog, then copies sourcePath there; returns the new location or null (Android, iOS, macOS, Windows, Linux). await UFile.saveAs(sourcePath: p, fileName: "invoice.pdf")
Implementation
static Future<String?> saveAs({required String sourcePath, required String fileName, String? mimeType}) => UFilesChannel.saveAs(sourcePath: sourcePath, fileName: fileName, mimeType: mimeType);