+ /**
+ * Some paths which were attempted failed to send, though possibly not all. At least some
+ * paths have irrevocably committed to the HTLC and retrying the payment in full would result
+ * in over-/re-payment.
+ *
+ * The results here are ordered the same as the paths in the route object which was passed to
+ * send_payment, and any Errs which are not APIError::MonitorUpdateFailed can be safely
+ * retried (though there is currently no API with which to do so).
+ *
+ * Any entries which contain Err(APIError::MonitorUpdateFailed) or Ok(()) MUST NOT be retried
+ * as they will result in over-/re-payment. These HTLCs all either successfully sent (in the
+ * case of Ok(())) or will send once channel_monitor_updated is called on the next-hop channel
+ * with the latest update_id.
+ */