Function rcu_drop 

pub fn rcu_drop<T: RcuDroppable + Sync>(value: T)

Schedule the object to be dropped after all in-flight read operations have completed.

To wait until the object is dropped, call rcu_synchronize(). Note that rcu_synchronize() requires an advancer thread or a thread calling rcu_run_callbacks() to make progress and drop the object.

To be safely passed to rcu_drop either directly, or indirectly by an rcu container, the type must implement the marker trait RcuDroppable to indicate:

• Dropping T must not take locks or otherwise block.
• It is safe to drop T from an arbitrary thread.
• There is no guarantee as to when T will actually be dropped unless rcu_synchronize() or rcu_run_callbacks() is called.