Uninitialized scalar field

The field will contain an arbitrary value left over from earlier computations. A scalar field is not initialized by the constructor
/src/mongo/db/ftdc/file_reader.h:134: UNINIT_CTOR 150762 Class member declaration for "_type".
/src/mongo/db/ftdc/file_reader.h:59: UNINIT_CTOR 150762 Non-static class member "_type" is not initialized in this constructor nor in any functions that it calls.