Function catch_unwind_str 

pub fn catch_unwind_str<F, R>(f: F) -> Result<R, Cow<'static, str>>
where
    F: FnOnce() -> R + UnwindSafe,

Available on crate feature panic and non-target_family=wasm only.

Like crate::panic::catch_unwind, but downcasts the returned Box<dyn Any> error to a string which is almost always is.