* push a new BodyContent to Stack
* @return new BodyContent
*/
public BodyContent push() {
if(current.after==null) {
current.after=new Entry(current,new BodyContentImpl(current.body==null?(JspWriter)base:current.body));
}
else {
current.after.doDevNull=false;
current.after.body.init(current.body==null?(JspWriter)base:current.body);
}