/// This definition will evolve as we go along.
#[derive(Debug, Hash)]pubstructFrame{#[cfg(target_pointer_width ="32")]pubip:u32,
#[cfg(target_pointer_width ="64")]pubip:u64,
}pubtypeSample=Vec<Frame>;// TODO: Generalize i32 error type to use failure.
pubtraitUnwinder<T> {/// Unwind a stack from a context.
////// Returns the collected frames.
fnunwind(self, context: T)->Result<Sample, i32>;}