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## Problem As documented, the global connection pool will be high contention. ## Summary of changes Use DashMap rather than Mutex<HashMap>. Of note, DashMap currently uses a RwLock internally, but it's partially sharded to reduce contention by a factor of N. We could potentially use flurry which is a port of Java's concurrent hashmap, but I have no good understanding of it's performance characteristics. Dashmap is at least equivalent to hashmap but less contention. See the read heavy benchmark to analyse our expected performance <https://github.com/xacrimon/conc-map-bench#ready-heavy> I also spoke with the developer of dashmap recently, and they are working on porting the implementation to use concurrent HAMT FWIW