The goal of this task is to refactor the MaxDiff implementation to make code more understandable and efficient. Key changes that need to be made can be found in the comments of this pull request. These include:

• Renaming _bounds to _bucketBounds in DataDistribution struct (TODO)
• Changing the structure of DataDistribution to use one array to store buckets, each of which is a struct containing the information on bounds and statistics (TODO)
• Renaming ValFreq to ValStats (TODO)

Also, run performance benchmark to see if there is any performance difference.