A way to check if an off mesh link is nearby?

I cannot find a built in function for what I'm looking for. I'm using generated off mesh links so there aren't actual gameobjects I could search for. NavMeshAgent.isOnOffMeshLink seems to work only if the agent is already in progress of transitioning to the target off mesh point. I'm basically trying to build a climb-on-a-ledge system with this. Any ideas or advice? Thanks.