L1ToL2CrossDomainMessengerGatewayAdapterStorage

struct L1ToL2CrossDomainMessengerGatewayAdapterStorage {
    /// @notice The paired-domain (counterpart) chain id (0 = unset). A canonical L1<->L2 pair has exactly ONE
    ///         other domain, so there is no chainId map. APPEND-ONLY.
    uint256 _counterpartChainId;
    /// @notice Trusted counterpart gateway adapter (the sibling adapter on the paired domain; 0 = unset).
    ///         APPEND-ONLY.
    address _counterpartAdapter;
    /// @notice The `minGasLimit` the messenger relays outbound messages with. APPEND-ONLY.
    uint32 _minGasLimit;
    /// @notice Replay guard: the set of consumed message ids. Single counterpart, so keyed by id alone.
    ///         APPEND-ONLY.
    mapping(bytes32 id => bool used) _executed;
    /// @notice Monotonic outbound counter. The messenger's `sendMessage` returns VOID (no per-message id to the
    ///         delivery target), so each dispatched message carries this source-minted nonce, giving a
    ///         globally-unique (counterpart, nonce) id on delivery (matching the CCIP/LayerZero/Wormhole siblings).
    uint256 _outboundNonce;
}