InboundLanes: StorageDescriptor<[Key: FixedSizeBinary<4>], {
    last_confirmed_nonce: bigint;
    relayers: {
        messages: {
            begin: bigint;
            end: bigint;
        };
        relayer: SS58String;
    }[];
    state: Enum<{
        Closed: undefined;
        Opened: undefined;
    }>;
}, true>

Map of lane id => inbound lane data.