/* The next cut of this method should also inspect the FO to see
* whether the area to be returned ought not to be the footnote
* or before-float reference area.*/
this.isNewSpanArea = false;
Span span = Span.NONE;
if (fo instanceof Block) {
span = ((Block) fo).traitSpan(this);
} else if (fo instanceof BlockContainer) {
span = ((BlockContainer) fo).traitSpan(this);
}