Why the above code generates an error of XmlTextWriter?Code:// using System; using System.Drawing; using System.Windows.Forms; using System.Runtime.InteropServices; using System.Xml; // pDoc = new XmlDocument(); XmlProcessingInstruction pPI = pDoc.CreateProcessingInstruction("xml", "version='1.0' encoding='ISO-8859-1'"); pDoc.AppendChild(pPI); XmlTextWriter writer = new XmlTextWriter("boop.xml", null); writer.Formatting = Formatting.Indented; pDoc.Save(writer); writer.Flush();