toJson method
Implementation
@visibleForTesting
Map<String, dynamic> toJson() => {
      "left": left,
      "top": top,
      "right": right,
      "bottom": bottom,
    }.clearNulls();@visibleForTesting
Map<String, dynamic> toJson() => {
      "left": left,
      "top": top,
      "right": right,
      "bottom": bottom,
    }.clearNulls();