pub struct Unwinder {
unwinding: bool,
}impl Unwinderfn try(&mut self, f: &fn())fn begin_unwind(&mut self) -> !
Prefix searches with a type followed by a colon (e.g.
fn:) to restrict the search to a given type.
Accepted types are: fn, mod,
struct (or str), enum,
trait, typedef (or
tdef).