add callout for minpoolsize

Author: stephmarie17

source/connect/connection-options/connection-pools.txt

@@ -165,6 +165,18 @@ object:
      minPoolSize: 10
    });
 
+.. note::
+
+   A ``MongoClient`` configured with ``maxIdleTimeMS`` and ``minPoolSize`` 
+   set to ``0`` is optimal for workloads with sustained periods of low activity. 
+   This configuration allows the connection pool to close unused connections 
+   during periods of inactivity. 
+   
+   In versions prior to 6.18.0, idle connections were not cleaned up when
+   ``minPoolSize`` was set to ``0``. Starting in version 6.18.0, the connection
+   pool correctly cleans up idle connections regardless of the ``minPoolSize``
+   setting.
+
 .. _node-connection-pool-max-idle-time:
 
 maxIdleTimeMS