Detect number of particles in area Flex in Unity

Im trying to detect the number of particles in a certain area in Unity (from https://assetstore.unity.com/packages/tools/physics/nvidia-flex-for-unity-1-0-beta-120425)

I’ve been scanning through the cs scripts in the assets folder. The FlexArrayActor.cs contains the m_asset instance of the FlexArrayAsset class. Within this is the m_asset.particles array, this shows the particles position on the instance of creation, however, this does not update after this.

Is there any way I can get the realtime information of the particles, so that this can be used to detect how many particles are within a certain area? This is for research purposes.

Hope anyone can help, been stuck with this for a while, Thanks!