gtreap is an immutable treap implementation in the Go Language

 Gtreap implements an immutable treap data structure in golang.
 .
 By treap, this data structure is both a heap and a binary search tree.
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 By immutable, any updates/deletes to a treap will return a new treap
 which can share internal nodes with the previous treap. All nodes in this
 implementation are read-only after their creation. This allows concurrent
 readers to operate safely with concurrent writers as modifications only
 create new data structures and never modify existing data structures.
 This is a simple approach to achieving MVCC or multi-version concurrency
 control.
 .
 By heap, items in the treap follow the heap-priority property, where a
 parent node will have higher priority than its left and right children
 nodes.
 .
 By binary search tree, items are store lexigraphically, ordered by a
 user-supplied Compare function.