Add missing golang-lru files

vendor/github.com/hashicorp/golang-lru/doc.go

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+// Package lru provides three different LRU caches of varying sophistication.
+//
+// Cache is a simple LRU cache. It is based on the
+// LRU implementation in groupcache:
+// https://github.com/golang/groupcache/tree/master/lru
+//
+// TwoQueueCache tracks frequently used and recently used entries separately.
+// This avoids a burst of accesses from taking out frequently used entries,
+// at the cost of about 2x computational overhead and some extra bookkeeping.
+//
+// ARCCache is an adaptive replacement cache. It tracks recent evictions as
+// well as recent usage in both the frequent and recent caches. Its
+// computational overhead is comparable to TwoQueueCache, but the memory
+// overhead is linear with the size of the cache.
+//
+// ARC has been patented by IBM, so do not use it if that is problematic for
+// your program.
+//
+// All caches in this package take locks while operating, and are therefore
+// thread-safe for consumers.
+package lru

vendor/github.com/hashicorp/golang-lru/simplelru/lru_interface.go

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+package simplelru
+
+
+// LRUCache is the interface for simple LRU cache.
+type LRUCache interface {
+  // Adds a value to the cache, returns true if an eviction occurred and
+  // updates the "recently used"-ness of the key.
+  Add(key, value interface{}) bool
+
+  // Returns key's value from the cache and
+  // updates the "recently used"-ness of the key. #value, isFound
+  Get(key interface{}) (value interface{}, ok bool)
+
+  // Check if a key exsists in cache without updating the recent-ness.
+  Contains(key interface{}) (ok bool)
+
+  // Returns key's value without updating the "recently used"-ness of the key.
+  Peek(key interface{}) (value interface{}, ok bool)
+
+  // Removes a key from the cache.
+  Remove(key interface{}) bool
+
+  // Removes the oldest entry from cache.
+  RemoveOldest() (interface{}, interface{}, bool)
+
+  // Returns the oldest entry from the cache. #key, value, isFound
+  GetOldest() (interface{}, interface{}, bool)
+
+  // Returns a slice of the keys in the cache, from oldest to newest.
+  Keys() []interface{}
+
+  // Returns the number of items in the cache.
+  Len() int
+
+  // Clear all cache entries
+  Purge()
+}