note static method
Record the page now on top: named when it has a route name;
unnamedDepth counts the unnamed pages stacked above the last named one.
Implementation
static void note({required bool named, int unnamedDepth = 0}) {
_unnamed = !named;
_unnamedDepth = named ? 0 : (unnamedDepth < 1 ? 1 : unnamedDepth);
}