Err  error     // Error returned by the remote peer for an rpc call
}

// A NotificationGroup is a collection of goroutines working on subtasks that are part of
// the same overall task.
//
// A zero NotificationGroup is valid and does not cancel on error.
type NotificationGroup struct {
	workers    *workers.Workers
	errs       []NotificationPeerErr
	retryCount int
}