docs: function transform(chunk, encoding, cb) {
      // only transform for raw bytes
      if (raw) {
        var response = BSON.deserialize(chunk);
        response.cursor.firstBatch.forEach(function(doc) {
          this.push(BSON.serialize(doc));
        }.bind(this));
        return cb();
      }
      // otherwise go back to the main stream
      return cb(null, chunk);
    }