You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: VoxelGridFilter.m
    path of file: ./repos/Autoware_Toolbox/benchmark/sensing/filters/points_downsampler/voxel_grid_filter
    
    the code of the file until where you have to start completion: classdef VoxelGridFilter < handle
    % VoxelGridFilter Downsampling point cloud using a voxel grid filte
    
function delete(obj) %#ok<INUSD>
            disp('Delete VoxelGridFilter object.');
        end
    end
    
    methods (Access = private)
        function [] = voxelGridFilterCallback(obj, sub, msg) %#ok<INUSL>
            % voxelGridFilterCallback Callback that runs when the subscriber object handle receives a topic message
            pt_cloud = pointCloud(msg.readXYZ(), 'intensity', msg.readField('intensity'));
            pt_cloud.Color = cast(horzcat(pt_cloud.Intensity, pt_cloud.Intensity, pt_cloud.Intensity), 'uint8');
            filtered_pt_cloud = pcdownsample(pt_cloud, 'gridAverage', obj.grid_step);
            filtered_pt_cloud.Intensity = cast(filtered_pt_cloud.Color(:, 1), 'single');
            pt_msg = PointCloudToPointCloud2(filtered_pt_cloud, msg.Header);
            send