What is the state of m_b_union_all_dimensions in OperatorUnionCursor

I was looking at the source for `OperatorUnionCursor`, [and found `m_b_union_all_dimensions` flag](https://github.com/Esri/geometry-api-java/blob/master/src/main/java/com/esri/core/geometry/OperatorUnionCursor.java#L41). I am curious what the intent of it is? It seems to always be set to false. Is the intent to one day allow support for `OperatorUnionCursor` to support multiple dimensions (as opposed to current behavior, which drops the lowest dimensions)? If that's what it was intended for, do we think it's feasible to modify this code to allow setting it to true when we want to allow support for unioning multiple dimensions of geometries with this operator?