EdgeInsets padding

The amount to pad the child in each dimension.

Source 

EdgeInsets get padding => _padding;
void padding=(EdgeInsets value)

Source 

set padding (EdgeInsets value) {
  assert(value != null);
  assert(value.isNonNegative);
  if (_padding == value)
    return;
  _padding = value;
  markNeedsLayout();
}