I have a system for drawing millions of tree instances which works by drawing procedural billboards using a geometry shader, which I am trying to port to URP. I have the basic rendering working already by submitting DrawProcedural via the ScriptableRenderContext in the Execute function of a custom ScriptableRendererFeature. I'm a little lost on how I would go about submitting shadow map draw calls however, since there is no RenderPassEvent.BeforeRenderingShadowMap. Previously, I used Graphics.DrawProcedural with the castShadows parameter set to true. What would be the equivalent in URP?