func NewBundle(parent context.Context) *Bundle {
	b := &Bundle{}
	b.context, b.cancel = context.WithCancel(parent)

	return b
}
func NewBundle(parent context.Context) *Bundle {
	b := &Bundle{}
	b.context, b.cancel = context.WithCancel(parent)

	return b
}
// Create a bundle whose operations are fed a context inheriting from the given
// parent context, which must be non-nil. The bundle must eventually be joined
// with Join.