what is differencebetween spacing and runSpacing in Flutter Wrap() Widget?

what is difference between spacing and run space named parameter Flutter Wrap() Widget and also run alignment property please explain that

>Solution :

spacing is the space between the children in the main axis and runSpacing is the space in the cross axis.

Consider this example (for default alignment)

SizedBox(
  width: 300,
  child: Wrap(
    spacing: 20.0, // Horizontal space.
    runSpacing: 30.0, // Vertical space.
    children: <Widget>[
      apple,
      ball,
      champion,
      destructor,
      eagle,
    ],
  ),
)