records () {
    const result = this._result.pipe(
      mergeMap(
        result =>
          new Observable(recordsObserver =>
            this._startStreaming({ result, recordsObserver })
          )
      )
    )
    result.push = () => this._push()
    return result
  }
Returns an observable that exposes each record returned by the executing query.

Errors raised during the streaming phase can surface on the returned observable stream.

@public
@returns {Observable<Record>} - An observable stream of records.