Vendor things

third-party/vendor/lru/README.md

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+# LRU Cache
+
+[![Travis Badge]][build status]
+[![Codecov Badge]][coverage status]
+[![crates.io Badge]][crates.io package]
+[![docs.rs Badge]][docs.rs documentation]
+[![License Badge]][license]
+
+[Documentation]
+
+An implementation of a LRU cache. The cache supports `put`, `get`, `get_mut` and `pop` operations,
+all of which are O(1). This crate was heavily influenced by the [LRU Cache implementation in an
+earlier version of Rust's std::collections crate].
+
+The MSRV for this crate is 1.64.0.
+
+## Example
+
+Below is a simple example of how to instantiate and use a LRU cache.
+
+```rust,no_run
+extern crate lru;
+
+use lru::LruCache;
+use std::num::NonZeroUsize;
+
+fn main() {
+    let mut cache = LruCache::new(NonZeroUsize::new(2).unwrap());
+    cache.put("apple", 3);
+    cache.put("banana", 2);
+
+    assert_eq!(*cache.get(&"apple").unwrap(), 3);
+    assert_eq!(*cache.get(&"banana").unwrap(), 2);
+    assert!(cache.get(&"pear").is_none());
+
+    assert_eq!(cache.put("banana", 4), Some(2));
+    assert_eq!(cache.put("pear", 5), None);
+
+    assert_eq!(*cache.get(&"pear").unwrap(), 5);
+    assert_eq!(*cache.get(&"banana").unwrap(), 4);
+    assert!(cache.get(&"apple").is_none());
+
+    {
+        let v = cache.get_mut(&"banana").unwrap();
+        *v = 6;
+    }
+
+    assert_eq!(*cache.get(&"banana").unwrap(), 6);
+}
+```
+
+[travis badge]: https://travis-ci.org/jeromefroe/lru-rs.svg?branch=master
+[build status]: https://travis-ci.org/jeromefroe/lru-rs
+[codecov badge]: https://codecov.io/gh/jeromefroe/lru-rs/branch/master/graph/badge.svg
+[coverage status]: https://codecov.io/gh/jeromefroe/lru-rs
+[crates.io badge]: https://img.shields.io/crates/v/lru.svg
+[crates.io package]: https://crates.io/crates/lru/
+[documentation]: https://docs.rs/lru/
+[docs.rs badge]: https://docs.rs/lru/badge.svg
+[docs.rs documentation]: https://docs.rs/lru/
+[license badge]: https://img.shields.io/badge/license-MIT-blue.svg
+[license]: https://raw.githubusercontent.com/jeromefroe/lru-rs/master/LICENSE
+[lru cache implementation in an earlier version of rust's std::collections crate]: https://doc.rust-lang.org/0.12.0/std/collections/lru_cache/struct.LruCache.html