func NewDataFileReader(ctx context.Context, n *mdag.Node, pb *ftpb.Data, serv mdag.DAGService) *DagReader { fctx, cancel := context.WithCancel(ctx) promises := serv.GetDAG(fctx, n) return &DagReader{ node: n, serv: serv, buf: NewRSNCFromBytes(pb.GetData()), promises: promises, ctx: fctx, cancel: cancel, pbdata: pb, } }