zfs diff - add an option for relative file (/directory) size differences, modification time, more?

[ge79so]

Describe the feature would like to see added to OpenZFS

Add an option to zfs diff to show relative size differences (eg. +/-n b/K/M/G etc) and modification time

How will this feature improve OpenZFS?

This is helpful when analysing differences between snapshots, especially where overall size is unexpected. It is currently possible to construct this information by comparing snapshot/dataset directory listings in a script, but this is rather fiddly.