(mongodb >=1.4.0)
MongoDB\Driver\Session::getOperationTime — Returns the operation time for this session
Returns the operation time for this session. If the session has not been used
for any operation and
MongoDB\Driver\Session::advanceOperationTime() has not
been called, the operation time will be null
Cette fonction ne contient aucun paramètre.
Returns the operation time for this session, or null if the session has no
operation time.