toJson method
Implementation
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = <String, dynamic>{};
data['time'] = time;
data['open'] = open;
data['close'] = close;
data['high'] = high;
data['low'] = low;
data['vol'] = vol;
data['amount'] = amount;
data['ratio'] = ratio;
data['change'] = change;
return data;
}