base: baseEvent{
			typ:  mappedType,
			time: Time(ev.Ts),
			args: mappedArgs,
		},
	}
	return out, nil
}

// convertOldFormat takes a fully loaded trace in the old trace format and
// returns an iterator over events in the new format.
func convertOldFormat(pr oldtrace.Trace) *oldTraceConverter {
	it := &oldTraceConverter{}
	it.init(pr)
	return it

		return nil, err
	}
	switch v {
	case version.Go111, version.Go119, version.Go121:
		tr, err := oldtrace.Parse(br, v)
		if err != nil {
			return nil, err
		}
		return &Reader{
			go121Events: convertOldFormat(tr),
		}, nil
	case version.Go122, version.Go123:
		return &Reader{
			r: br,
			order: ordering{
				mStates:     make(map[ThreadID]*mState),
				pStates:     make(map[ProcID]*pState),