Compare pre-edit geometry with edited geometry

BB1234

In an Arcade attribute rule:

Is there a way to compare a feature's geometry before the edit was made...
vs.
...the edited geometry?

Example:
If the pre-edit geometry is different from the edited geometry, then do x to the geometry.
Else, do nothing.

Related: Attribute Rules: Update only on geometry change

I was hoping I'd be able to use $feature.shape as to get the pre-edit geometry. But that failed. Which is weird, because I can use $feature.shape_length without issue.

BB1234

For my records, here's where the $originalfeature global variable can be found in the docs:

Attribute Rule Calculation

Globals

Variable Name Type Description

$datastore	FeatureSetCollection	A collection of layers in the same feature service or database as the$featureexecuting the script.
$editcontext.editType	Text	Indicates whether the edit event isINSERT,UPDATE,DELETE, or NA(not applicable).
$feature	Feature	The feature being calculated.
$originalFeature	Feature	The previous state of the feature being calculated.
$featureSet	FeatureSet	A collection of features in the same table as the$featureevaluating the expression.

Related: 

 - Identify whether a specific attribute value has changed
 - Arcade: Editing M-values not treated as change to geometry