Using `delete` instead of setting mapping/struct to 0 saves gas

deleteCheaperThanAssignment.sol

pragma solidity 0.8.19;

contract Gas {
    mapping(uint256 => uint256) test;

    function notOptimized() external returns(uint gasUsed){        
        uint startGas = gasleft();
        test[1234] = 0; // 2299
        gasUsed = startGas - gasleft();
    }

    function optimized() external returns(uint gasUsed){        
        uint startGas = gasleft();
        delete test[1234]; // 2294
        gasUsed = startGas - gasleft();
    }    
}