hyperlane-monorepo/solidity/contracts/libs/hooks/OPStackHookMetadata.sol

// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity >=0.8.0;

/**
 * Format of metadata:
 *
 * [0:32] Msg value to be sent to L2
 */
library OPStackHookMetadata {
    function msgValue(bytes calldata _metadata)
        internal
        pure
        returns (uint256)
    {
        return uint256(bytes32(_metadata[0:32]));
    }
}