code: @Nonnull
    public ApiFuture<QuerySnapshot> get(@Nonnull Query query) {
      Preconditions.checkState(isEmpty(), READ_BEFORE_WRITE_ERROR_MSG);
  
      return query.get(transactionId);
    }
docs: Returns the result set from the provided query. Holds a pessimistic lock on all returned
  documents.
  
  @return The contents of the Document at this DocumentReference.