fix: gracefully close pool connections sidorares#3148

Author: dimov

lib/pool.js

@@ -205,7 +205,7 @@ class Pool extends EventEmitter {
             Date.now() - this._freeConnections.get(0).lastActiveTime >
               this.config.idleTimeout)
         ) {
-          this._freeConnections.get(0).destroy();
+          this._freeConnections.get(0)._realEnd();
         }
       } finally {
         this._removeIdleTimeoutConnections();