Initial QSfera import

Server/vendor/github.com/jellydator/ttlcache/v3/metrics.go

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+package ttlcache
+
+// Metrics contains common cache metrics calculated over the course
+// of the cache's lifetime.
+type Metrics struct {
+	// Insertions specifies how many items were inserted.
+	Insertions uint64
+
+	// Updates specifies how many items were updated.
+	Updates uint64
+
+	// Hits specifies how many items were successfully retrieved
+	// from the cache.
+	// Retrievals made with a loader function are not tracked.
+	Hits uint64
+
+	// Misses specifies how many items were not found in the cache.
+	// Retrievals made with a loader function are considered misses as
+	// well.
+	Misses uint64
+
+	// Evictions specifies how many items were removed from the
+	// cache.
+	Evictions uint64
+}