Implement RefUnwindSafe for Backtrace Backtrace doesn't have visible mutable state. See also https://internals.rust-lang.org/t/should-backtrace-be-refunwindsafe/17169?u=xfix
Implement RefUnwindSafe for Backtrace Backtrace doesn't have visible mutable state. See also https://internals.rust-lang.org/t/should-backtrace-be-refunwindsafe/17169?u=xfix