static void AddGlobalNamespaceImport (MonoDevelop.Ide.Editor.TextEditor editor, DocumentContext context, string nsName)
{
var parsedDocument = context.ParsedDocument;
var unit = parsedDocument.GetAst<SemanticModel> ();
if (unit == null)
return;
int offset = SearchUsingInsertionPoint (unit.SyntaxTree.GetRoot ());
var text = new StringBuilder ();
text.Append ("using ");
text.Append (nsName);
text.Append (";");
text.Append (editor.EolMarker);
editor.InsertText (offset, text.ToString ());
}