Data race condition

The value of the shared data will be determined by the interleaving of thread execution. Thread shared data is accessed without holding an appropriate lock, possibly causing a race condition
/src/mongo/db/repl/topology_version_observer.cpp:191: MISSING_LOCK 144839 Accessing "this->_serviceContext" without holding lock "mongo::repl::TopologyVersionObserver._mutex". Elsewhere, "mongo::repl::TopologyVersionObserver._serviceContext" is written to with "TopologyVersionObserver._mutex" held 1 out of 1 times (1 of these accesses strongly imply that it is necessary).