public Task <ResourceResponse <Document> > UpdateHeartrateAsync(HeartrateData heartrate)
        {
            var doc = Client.CreateDocumentQuery <Document>(Collection.DocumentsLink)
                      .Where(d => d.Id == heartrate.ID)
                      .AsEnumerable() // why the heck do we need to do this??
                      .FirstOrDefault();

            return(Client.ReplaceDocumentAsync(doc.SelfLink, heartrate));
        }
 public Task <ResourceResponse <Document> > CreateHeartrate(HeartrateData heartrate)
 {
     return(Client.CreateDocumentAsync(Collection.DocumentsLink, heartrate));
 }