AutoLayoutRect rect

Parameters that represent the size and position of the render box.

Source 

AutoLayoutRect get rect => _rect;
void rect=(AutoLayoutRect value)

Source 

set rect(AutoLayoutRect value) {
  if (_rect == value)
    return;
  if (_rect != null)
    _removeImplicitConstraints();
  _rect = value;
  if (_rect != null)
    _addImplicitConstraints();
}