function flattenUnsubscriptionErrors(errors) {
    return errors.reduce(function (errs, err) { return errs.concat((err instanceof UnsubscriptionError_1.UnsubscriptionError) ? err.errors : err); }, []);
}
Removes a Subscription from the internal list of subscriptions that will
unsubscribe during the unsubscribe process of this Subscription.
@param {Subscription} subscription The subscription to remove.
@return {void}