Make request and parse response

private func loadMoreListings() {
    if listingViewModelsLegacy.value == nil {
        loadingEvents.on(.next(.loadingList))
    }

    guard let searchQuery = SearchQuery.deepCopy(model: searchQuery) else {
        return
    }

    currentListRequest?.cancel()
    currentListRequest = nil

    searchQuery.geography = nil
    searchQuery.num = 25
    searchQuery.start = 0
    searchQuery.sortOrder = .l1ScoreConsumerDown
    searchQuery.agentSearch = nil
    searchQuery.includeInContract = true
    searchQuery.centerPoint = nil
    searchQuery.mapSearchProperties = nil
    searchQuery.latestTransactionOnly = false
    searchQuery.connectedGeos = nil
    searchQuery.facetFieldNames = [SearchQueryFacetConstants.fieldKeys.comingSoon.rawValue]
    searchQuery.zoomLevel = nil

    let request = SearchRelationsRequest()
    request.searchQuery = searchQuery
    request.relationTypes = [.boards]

    currentListRequest = userListingRelationService.listSearchRelations(request: request, onNext: { [weak self] response, source in
        guard source == .network else {
            return
        }
        self?.update(listingRelations: response.listingRelations ?? [])
        if let totalResults = response.totalNumResults {
            self?.totalResults.value = totalResults
        }
        if self?.totalResults.value == 0 {
            self?.loadingEvents.on(.next(.pageLoaded(page: .zero)))
            return
        }
        self?.loadingEvents.on(.next(.idle))
    }, onError: { [weak self] error in
        if error.code == NSURLErrorCancelled {
            return
        }
        self?.loadingEvents.on(.next(.idle))
    })
}

private func update(listingRelations: [ProcessedListingRelation]) {
    let showStar = true
    let newListings = ListingCardViewModelLegacy.fromListingRelations(listingRelations,
                                                                      isAgent: user?.isAgent ?? false,
                                                                      photoInteractionEnabled: true,
                                                                      isSelectable: false,
                                                                      showStar: showStar)

    listingViewModelsLegacy.value = newListings.nilIfEmpty

    loadingEvents.on(.next(.pageLoaded(page: Page.zero)))
}