Possbile data race in tokio-timer Entry
Struct Entry implements Sync trait so as to be shared across threads by reference. It contains UnsafeCell, and its methods will return a mutable reference to the inner data.
This may cause a crash if one thread writes the data while another is accessing it, all by immutable reference of the struct and will bypass compiler checking. It is rather unsafe but we marked it as safe!!!
In fact, tokio-timer has a number of problems. I think the misuse of interior mutability may be the root cause of the crashes.
I searched for a newer version of the same functionality, but much safer.
My suggestion is to replace the current buggy one with this version.