z.IfNoneMatch, bts, err = msgp.ReadStringBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "IfNoneMatch")
				return
			}
		case "IfModifiedSince":
			if msgp.IsNil(bts) {
				bts, err = msgp.ReadNilBytes(bts)
				if err != nil {
					return
				}
				z.IfModifiedSince = nil
			} else {
				if z.IfModifiedSince == nil {
					z.IfModifiedSince = new(time.Time)
				}