Design a Ten-Minute In-Memory Notification Deduplication Engine

You are asked to design a service that suppresses duplicate notifications within a short time window. The service must run entirely in memory, with no persistent storage. For a given notification key, only one notification should be forwarded to downstream consumers during any rolling ten-minute interval. A notification includes a string key supplied by the caller. Two notifications with the same key are considered duplicates. The deduplication logic uses the arrival time of…