Define and signal the staging zero reserve feature

Author: tankyleo

lightning-types/src/features.rs

@@ -175,6 +175,8 @@ mod sealed {
 			,
 			// Byte 19
 			HtlcHold,
+			// Byte 20
+			ZeroReserveStaging,
 		]
 	);
 	define_context!(
@@ -204,8 +206,10 @@ mod sealed {
 			,
 			// Byte 19
 			HtlcHold,
-			// Byte 20 - 31
-			,,,,,,,,,,,,
+			// Byte 20
+			ZeroReserveStaging,
+			// Byte 21 - 31
+			,,,,,,,,,,,
 			// Byte 32
 			DnsResolver,
 		]
@@ -721,6 +725,17 @@ mod sealed {
 		supports_htlc_hold,
 		requires_htlc_hold
 	);
+	define_feature!(
+		165,
+		ZeroReserveStaging,
+		[InitContext, NodeContext],
+		"Feature flags for zero reserve.",
+		set_zero_reserve_optional,
+		set_zero_reserve_required,
+		clear_zero_reserve,
+		supports_zero_reserve,
+		requires_zero_reserve
+	);
 	define_feature!(
 		259,
 		DnsResolver,

lightning/src/ln/channelmanager.rs

@@ -17017,6 +17017,7 @@ pub fn provided_init_features(config: &UserConfig) -> InitFeatures {
 	features.set_simple_close_optional();
 	features.set_quiescence_optional();
 	features.set_splicing_optional();
+	features.set_zero_reserve_optional();
 
 	if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx {
 		features.set_anchors_zero_fee_htlc_tx_optional();

lightning/src/ln/peer_handler.rs

@@ -413,6 +413,7 @@ impl BaseMessageHandler for ErroringMessageHandler {
 		features.set_scid_privacy_optional();
 		features.set_zero_conf_optional();
 		features.set_route_blinding_optional();
+		features.set_zero_reserve_optional();
 		#[cfg(simple_close)]
 		features.set_simple_close_optional();
 		features