double maxWidth

The value to use for maxWidth if the incoming maxWidth constraint is infinite.

Source 

double get maxWidth => _maxWidth;
void maxWidth=(double value)

Source 

set maxWidth (double value) {
  assert(value != null && value >= 0.0);
  if (_maxWidth == value)
    return;
  _maxWidth = value;
  markNeedsLayout();
}