Expose the outgoing HTLC's CLTV expiry in `Event::HTLCIntercepted`

diff --git a/lightning/src/events/mod.rs b/lightning/src/events/mod.rs
index 277ce61..b029caa 100644
--- a/lightning/src/events/mod.rs
+++ b/lightning/src/events/mod.rs
@@ -1287,6 +1287,13 @@ pub enum Event {
 		/// [`Self::HTLCIntercepted::inbound_amount_msat`]) or subtract it as required. Further,
 		/// LDK will not stop you from forwarding more than you received.
 		expected_outbound_amount_msat: u64,
+		/// The block height at which the forwarded HTLC sent to our peer will time out. In
+		/// practice, LDK will refuse to forward an HTLC several blocks before this height (as if
+		/// we attempted to forward an HTLC at this height we'd run some risk that our peer
+		/// force-closes the channel immediately).
+		///
+		/// This will only be `None` for events generated or serialized by LDK 0.2 or prior.
+		outgoing_htlc_expiry_block_height: Option<u32>,
 	},
 	/// Used to indicate that an output which you should know how to spend was confirmed on chain
 	/// and is now spendable.
@@ -2017,11 +2024,13 @@ impl Writeable for Event {
 				inbound_amount_msat,
 				expected_outbound_amount_msat,
 				intercept_id,
+				outgoing_htlc_expiry_block_height,
 			} => {
 				6u8.write(writer)?;
 				let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
 				write_tlv_fields!(writer, {
 					(0, intercept_id, required),
+					(1, outgoing_htlc_expiry_block_height, option),
 					(2, intercept_scid, required),
 					(4, payment_hash, required),
 					(6, inbound_amount_msat, required),
@@ -2526,8 +2535,10 @@ impl MaybeReadable for Event {
 					InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
 				let mut inbound_amount_msat = 0;
 				let mut expected_outbound_amount_msat = 0;
+				let mut outgoing_htlc_expiry_block_height = None;
 				read_tlv_fields!(reader, {
 					(0, intercept_id, required),
+					(1, outgoing_htlc_expiry_block_height, option),
 					(2, requested_next_hop_scid, required),
 					(4, payment_hash, required),
 					(6, inbound_amount_msat, required),
@@ -2542,6 +2553,7 @@ impl MaybeReadable for Event {
 					inbound_amount_msat,
 					expected_outbound_amount_msat,
 					intercept_id,
+					outgoing_htlc_expiry_block_height,
 				}))
 			},
 			7u8 => {
diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index eeb5a53..fd5e5d1 100644
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -3409,6 +3409,7 @@ fn create_htlc_intercepted_event(
 		inbound_amount_msat,
 		expected_outbound_amount_msat: pending_add.forward_info.outgoing_amt_msat,
 		intercept_id,
+		outgoing_htlc_expiry_block_height: Some(pending_add.forward_info.outgoing_cltv_value),
 	})
 }
 
diff --git a/lightning/src/ln/payment_tests.rs b/lightning/src/ln/payment_tests.rs
index 8ac87fb..1444623 100644
--- a/lightning/src/ln/payment_tests.rs
+++ b/lightning/src/ln/payment_tests.rs
@@ -2277,6 +2277,7 @@ fn do_test_intercepted_payment(test: InterceptTest) {
 	// Check that we generate the PaymentIntercepted event when an intercept forward is detected.
 	let events = nodes[1].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 1);
+	let expected_cltv = nodes[0].best_block_info().1 + TEST_FINAL_CLTV + 1;
 	let (intercept_id, outbound_amt) = match events[0] {
 		crate::events::Event::HTLCIntercepted {
 			intercept_id,
@@ -2284,10 +2285,12 @@ fn do_test_intercepted_payment(test: InterceptTest) {
 			payment_hash,
 			inbound_amount_msat,
 			requested_next_hop_scid: short_channel_id,
+			outgoing_htlc_expiry_block_height,
 		} => {
 			assert_eq!(payment_hash, hash);
 			assert_eq!(inbound_amount_msat, route.get_total_amount() + route.get_total_fees());
 			assert_eq!(short_channel_id, intercept_scid);
+			assert_eq!(outgoing_htlc_expiry_block_height.unwrap(), expected_cltv);
 			(intercept_id, expected_outbound_amount_msat)
 		},
 		_ => panic!(),
@@ -2356,6 +2359,7 @@ fn do_test_intercepted_payment(test: InterceptTest) {
 			assert_eq!(events.len(), 1);
 			SendEvent::from_event(events.remove(0))
 		};
+		assert_eq!(payment_event.msgs[0].cltv_expiry, expected_cltv);
 		nodes[2].node.handle_update_add_htlc(node_b_id, &payment_event.msgs[0]);
 		let commitment = &payment_event.commitment_msg;
 		do_commitment_signed_dance(&nodes[2], &nodes[1], commitment, false, true);