Race sending transfer proof against cancel timelock

Sending the transfer proof might never resolve because Bob doesn't
come back online. In that case, we need to make sure we bail out
as soon as the timelock expires.

swap/src/protocol/alice/swap.rs

@@ -116,29 +116,32 @@ async fn next_state(
                 state3,
             },
         },
-
         AliceState::XmrLocked {
             monero_wallet_restore_blockheight,
             transfer_proof,
             state3,
-        } => match state3.expired_timelocks(bitcoin_wallet).await? {
+        } => {
-            ExpiredTimelocks::None => {
+            let tx_lock_status = bitcoin_wallet.subscribe_to(state3.tx_lock.clone()).await;
-                event_loop_handle
-                    .send_transfer_proof(transfer_proof.clone())
-                    .await?;
 
-                XmrLockTransferProofSent {
+            tokio::select! {
-                    monero_wallet_restore_blockheight,
+                result = event_loop_handle.send_transfer_proof(transfer_proof.clone()) => {
-                    transfer_proof,
+                   result?;
-                    state3,
+
+                   XmrLockTransferProofSent {
+                       monero_wallet_restore_blockheight,
+                       transfer_proof,
+                       state3,
+                   }
+                },
+                _ = tx_lock_status.wait_until_confirmed_with(state3.cancel_timelock) => {
+                    AliceState::CancelTimelockExpired {
+                        monero_wallet_restore_blockheight,
+                        transfer_proof,
+                        state3,
+                    }
                 }
             }
-            _ => AliceState::CancelTimelockExpired {
+        }
-                monero_wallet_restore_blockheight,
-                transfer_proof,
-                state3,
-            },
-        },
         AliceState::XmrLockTransferProofSent {
             monero_wallet_restore_blockheight,
             transfer_proof,