1. override
bool operator ==(other)

Equality operator. Compares an Offset or Size to another Offset or Size, and returns true if the horizontal and vertical values of the left-hand-side operand are equal to the horizontal and vertical values of the right-hand-side operand respectively. Returns false otherwise.

Source 

@override
bool operator ==(dynamic other) {
  if (other is! OffsetBase)
    return false;
  final OffsetBase typedOther = other;
  return _dx == typedOther._dx &&
         _dy == typedOther._dy;
}