Delegate functions are missing `Send` bound

Affected versions of this crate did not require event handlers to have Send bound despite there being no guarantee of them being called on any particular thread, which can potentially lead to data races and undefined behavior. The flaw was corrected in commit afe3252 by adding Send bounds...

RUSTSEC-2020-0060 futures_task::waker may cause a use-after-free if used on a type that isn't 'static

Affected versions of the crate did not properly implement a 'static lifetime bound on the waker function. This resulted in a use-after-free if Waker::wake is called after original data had been dropped. The flaw was corrected by adding 'static lifetime bound to the data waker takes...