public JTSGeometryExpression<Geometry> union(Geometry geometry) {
        return union(ConstantImpl.create(geometry));
    }
Returns a geometric object that represents the Point set
union of this geometric object with anotherGeometry.

@param geometry other geometry
@return union of this and the other geometry
querydsl-spatial/src/main/java/com/querydsl/spatial/locationtech/jts/JTSGeometryExpression.java