Bing search volume for a list of `keywords`. Returns `keyword`, `location_code`, `language_code`, `search_partners`, `device`, `competition`, `cpc`, `search_volume`, `categories` and `monthly_searches` - note `categories`, which the Google equivalent does not return, and no `competition_index`. Measured at 1.3 KB for one keyword, a fraction of the Google response. Measured at $0.09 upstream against $0.012 billed. Wrapped in DataForSEO's envelope: data in `tasks[0].result`, outcome in `tasks[0].status_code` - a rejected request still returns HTTP 200. The Google twin is `post_dataforseo_keywords_gads_search_volume_live`; run both when the audience is not Google-only. The submit and fetch twins of this endpoint do the same work asynchronously, at the same price, for batches too large to wait on.