DART

overflow box flutter

// this will give you any size you want not considering it's parent size and
// will also not give you any overflow error even if any(unlike unconstrained box)
OverflowBox(
      minWidth: 0.0,
      minHeight: 0.0,
      maxWidth: double.infinity,
      maxHeight: double.infinity,
      child: Container(color: red, width: 4000, height: 50),
    )