After a write txn is commited, we have to make the state as now RO. However, the caller, still has a ref to the txn, and may inadventantly call rotxn_close, which would cause txn decrement to be called. This would drop the root transaction to rc 0 and cause a gc. In the end, the tree is now burning to the ground.

During a commit, we should cope the btxn, content to a new txn, and the holder's txn should be invalidated.