Add logging for successful/failed probes

Author: tnull

lightning-invoice/src/payment.rs

@@ -599,8 +599,10 @@ where
 						// handler.
 						if self.payer.payment_is_probe(*payment_hash, *payment_id) {
 							if *rejected_by_dest {
+								log_trace!(self.logger, "Probe {} was successful", log_bytes!(payment_hash.0));
 								self.scorer.lock().probe_successful(&path);
 							} else {
+								log_trace!(self.logger, "Probe {} failed at channel {}", log_bytes!(payment_hash.0), *short_channel_id);
 								self.scorer.lock().probe_failed(&path, *short_channel_id);
 							}
 							return;