docs: private OperationResult applyCommand(long index, long sequence, long timestamp, PrimitiveOperation operation, RaftSession session) {
      long eventIndex = session.getEventIndex();
  
      Commit<byte[]> commit = new DefaultCommit<>(index, operation.id(), operation.value(), session, timestamp);
  
      OperationResult result;
      try {
        currentSession = session;
  
        // Execute the state machine operation and get the result.
        byte[] output = service.apply(commit);
  
        // Store the result for linearizability and complete the command.
        result = OperationResult.succeeded(index, eventIndex, output);
      } catch (Exception e) {
        // If an exception occurs during execution of the command, store the exception.
        result = OperationResult.failed(index, eventIndex, e);
      } finally {
        currentSession = null;
      }
  
      // Once the operation has been applied to the state machine, commit events published by the command.
      // The state machine context will build a composite future for events published to all sessions.
      commit();
  
      // Register the result in the session to ensure retries receive the same output for the command.
      session.registerResult(sequence, result);
  
      // Update the session timestamp and command sequence number.
      session.setCommandSequence(sequence);
  
      // Complete the command.
      return result;
    }