code: public CompletableFuture<OperationResult> executeQuery(
        long index,
        long sequence,
        long timestamp,
        RaftSession session,
        PrimitiveOperation operation) {
      CompletableFuture<OperationResult> future = new CompletableFuture<>();
      executeQuery(index, sequence, timestamp, session, operation, future);
      return future;
    }
docs: Executes the given query on the state machine.
  
  @param index     The index of the query.
  @param sequence  The query sequence number.
  @param timestamp The timestamp of the query.
  @param session   The session that submitted the query.
  @param operation The query to execute.
  @return A future to be completed with the query result.