Visits every node under roots (roots included) in source order, depth first, without recursion, so a chain of thousands of set operations is safe. visit receives each node and its parent (null for a root).
roots
visit
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Visits every node under
roots(roots included) in source order, depth first, without recursion, so a chain of thousands of set operations is safe.visitreceives each node and its parent (nullfor a root).