// use an existing PDF as a template for a new document
PDFDoc doc = new PDFDoc(filename);

// optionally perform some document processing using read write operations 
// found under 'Editing Page Content' or 'Page Manipulation'

// save the document to the filesystem
doc.Save(output_filename, SDFDoc.SaveOptions.e_linearized);

// optionally save the document to a memory buffer
byte[] buf = doc.Save(SDFDoc.SaveOptions.e_linearized);