+ type ExclLock;
+ /// If two instances of the same mutex are being taken at the same time, it's very easy to have
+ /// a lockorder inversion and risk deadlock. Thus, we default to disabling such locks.
+ ///
+ /// However, sometimes they cannot be avoided. In such cases, this method exists to take a
+ /// mutex while avoiding a test failure. It is deliberately verbose and includes the term
+ /// "unsafe" to indicate that special care needs to be taken to ensure no deadlocks are
+ /// possible.
+ fn unsafe_well_ordered_double_lock_self(&'a self) -> Self::ExclLock;