Add DispatchHook

solidity/contracts/hooks/DispatchedHook.sol

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.13;
+
+import {AbstractPostDispatchHook} from "./libs/AbstractPostDispatchHook.sol";
+import {IPostDispatchHook} from "../interfaces/hooks/IPostDispatchHook.sol";
+import {Message} from "../libs/Message.sol";
+
+/**
+ * @title DispatchedHook
+ * @notice Hook that updates a mapping to keep track of dispatched messages
+ */
+contract DispatchedHook is AbstractPostDispatchHook {
+    using Message for bytes;
+
+    mapping(uint256 messageNonce => bytes32 messageId) public dispatched;
+
+    /// @inheritdoc IPostDispatchHook
+    function hookType() external pure returns (uint8) {
+        return uint8(IPostDispatchHook.Types.DISPATCHED);
+    }
+
+    /**
+     * @notice Sets the dispatched mapping to be used for storage proofs in the Telepathy CCIP ISM.
+     * @param message Message to be dispatched
+     */
+    function _postDispatch(
+        bytes calldata,
+        bytes calldata message
+    ) internal virtual override {
+        dispatched[message.nonce()] = message.id();
+    }
+
+    /// @inheritdoc AbstractPostDispatchHook
+    function _quoteDispatch(
+        bytes calldata,
+        bytes calldata
+    ) internal view virtual override returns (uint256) {
+        return 0;
+    }
+}