(mongodb >=1.13.0)
The MongoDB\Driver\TopologyDescription class is a value object that represents a topology to which the driver is connected. Instances of this class are returned by MongoDB\Driver\Monitoring\TopologyChangedEvent methods.
MongoDB\Driver\TopologyDescription::TYPE_UNKNOWNMongoDB\Driver\TopologyDescription::TYPE_SINGLEMongoDB\Driver\TopologyDescription::TYPE_SHARDEDMongoDB\Driver\TopologyDescription::TYPE_REPLICA_SET_NO_PRIMARYMongoDB\Driver\TopologyDescription::TYPE_REPLICA_SET_WITH_PRIMARYMongoDB\Driver\TopologyDescription::TYPE_LOAD_BALANCED