(mongodb >=1.6.0)
MongoDB\Driver\Session::getServer — Returns the server to which this session is pinned
Returns the MongoDB\Driver\Server to which this
session is pinned. If the session is not pinned to a server, null will be
returned.
Session pinning is primarily used for sharded transactions, as all commands within a sharded transaction must be sent to the same mongos instance. This method is intended to be used by libraries built atop the extension to allow use of a pinned server instead of invoking server selection.
This function has no parameters.
Returns the MongoDB\Driver\Server to which this
session is pinned, or null if the session is not pinned to any server.