Fix channel

lib/lightning/channelconfig.dart

@@ -8,3 +8,21 @@ const ChannelConfig({
   required this.forceCloseAvoidanceMaxFeeSatoshis,
   required this.acceptUnderpayingHtlcs,
 });
+
+class ChannelConfigBuilder {
+  late int forwardingFeeProportionalMillionths;
+  late int forwardingFeeBaseMsat;
+  late int cltvExpiryDelta;
+  late int maxDustHtlcExposure;
+  late int forceCloseAvoidanceMaxFeeSatoshis;
+  late bool acceptUnderpayingHtlcs;
+}
+
+  ChannelConfigBuilder({
+    required this.forwardingFeeProportionalMillionths,
+    required this.forwardingFeeBaseMsat,
+    required this.cltvExpiryDelta,
+    required this.maxDustHtlcExposure,
+    required this.forceCloseAvoidanceMaxFeeSatoshis,
+    required this.acceptUnderpayingHtlcs,
+  });