Deleting from GeomVertexArrayData

I have a VertexWriter that I’m using with a node’s index to I can add and modify triangles like this:

geom = self.geomPath.node().modifyGeom(0)
prim = geom.modifyPrimitive(0)
indexdata = prim.modifyVertices()
indexwriter = GeomVertexRewriter(indexdata)

This works nicely for updating existing triangles and adding new ones. Is there any way to delete a triangle from the end of the list? Would I have to do an expensive copy to a new GeomVertexArrayData, or is there some way to reduce the size of the array?

Found my answer. Looks like you can call setNumRows on GeomVertexArrayData: