encode method Null safety

Implementation

Object encode() {
  final Map<Object?, Object?> pigeonMap = <Object?, Object?>{};
  pigeonMap['id'] = id;
  pigeonMap['geometry'] = geometry;
  pigeonMap['lineJoin'] = lineJoin?.index;
  pigeonMap['lineSortKey'] = lineSortKey;
  pigeonMap['lineBlur'] = lineBlur;
  pigeonMap['lineColor'] = lineColor;
  pigeonMap['lineGapWidth'] = lineGapWidth;
  pigeonMap['lineOffset'] = lineOffset;
  pigeonMap['lineOpacity'] = lineOpacity;
  pigeonMap['linePattern'] = linePattern;
  pigeonMap['lineWidth'] = lineWidth;
  return pigeonMap;
}