OfferResponse constructor Null safety
Implementation
OfferResponse(this.id, this.pagingToken, this.seller, this.selling, this.buying, this.amount,
this.price, this.sponsor, this.lastModifiedLedger, this.lastModifiedTime, this.links);
OfferResponse(this.id, this.pagingToken, this.seller, this.selling, this.buying, this.amount,
this.price, this.sponsor, this.lastModifiedLedger, this.lastModifiedTime, this.links);