operator == method
Returns true if other
is another Rect that creates the same rectangle
in 2D coordinate space as this rectangle (i.e., their top, right,
bottom, and left values are equivalent).
Implementation
@override
bool operator ==(Object other) {
if (other is! Rect) return false;
return top == other.top &&
right == other.right &&
bottom == other.bottom &&
left == other.left;
}