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/s/migration_destination_manager.cpp:1660: MISSING_LOCK 170234 Accessing "this->this->_txnNumber" without holding lock "mongo::MigrationDestinationManager._mutex". Elsewhere, "mongo::MigrationDestinationManager._txnNumber" is written to with "MigrationDestinationManager._mutex" held 2 out of 2 times.