Best Way to Update on Current Visible Nodes

[fkhaller]

When collapsing and expanding nodes there does not seem to be a simple way to know which nodes are visible. You can use the graphRef.current.getGraph() function to check on the current visible nodes but that is not a mutable state that I can use to update a visbleNodes state. If there was a reference to the visible nodes or a callback to when the graph finishes updating it should solve this dilemma.