CVE-2020-36445: Data races in convec

The vulnerability stems from improper trait implementations rather than specific functions. The ConVec<T> type unconditionally implements Send and Sync traits without enforcing that T: Send or T: Sync. This allows non-thread-safe types (e.g., Rc<T>, Cell<T>) to be used in concurrent contexts, leading to data races. The root cause is the unsafe unsafe impl<T> Send for ConVec<T> {} and unsafe impl<T> Sync for ConVec<T> {} blocks in the crate's implementation. These trait implementations violate Rust's safety guarantees by enabling cross-thread sharing of non-Send/Sync types. No specific functions are directly implicated; the flaw lies in the type's trait bounds.