reconnect() holds the pool slot while sleeping between attempts

`Session::reconnect()` sleeps `retry_interval` between passes and walks all endpoints while still holding its pool slot. With defaults (3 endpoints, 3 attempts, 1s interval) the worst case is ~92s, during which concurrent `acquire()` callers get "pool exhausted" — an error that points away from the real cause.

Fix: when the session is handed out from a pool, skip the between-attempt sleeps (the slot is still held, but the hold time drops to the connect+handshake attempts), or shorten them. Standalone sessions keep the current C#-style pacing.

Comece lendo Session::reconnect e o caminho do pool que entrega as sessões aos chamadores de acquire, concentrando-se em como as sessões pooled e standalone são identificadas. Verifique se as tentativas de reconnect pooled não mantêm os sleeps entre as tentativas, enquanto as sessões standalone mantêm seu pacing atual, e confirme que a aquisição concorrente do pool não falha mais por causa do atraso.

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