openFile static method
Opening the specified file.
For Web, filePath can be relative path from index.html or any
arbitrary URL but it may be restricted by CORS.
password supported only for web!
Implementation
static Future<PdfDocument> openFile(String filePath, {String? password}) {
assertHasPdfSupport();
return PdfxPlatform.instance.openFile(filePath, password: password);
}