(mongodb >=1.6.0)
MongoDB\Driver\Session::isInTransaction — Returns whether a multi-document transaction is in progress
Returns whether a multi-document transaction is currently in progress for this session. A transaction is considered "in progress" if it has been started but has not been committed or aborted.
この関数にはパラメータはありません。
Returns TRUE
if a transaction is currently in progress for this session,
and FALSE
otherwise.