Get Batched Contacts by IDs

**This endpoint is used to retrieve a set of contacts identified by their IDs.** This can be more efficient endpoint to get contacts than making a series of individual `GET` requests to the "Get a Contact by ID" endpoint. You can supply up to 100 IDs. Pass them into the `ids` field in your request body as an array or one or more strings. Twilio SendGrid recommends exporting your contacts regularly as a backup to avoid issues or lost data.