pragma solidity ^0.5.0;

contract Client {
    uint256 public t;

    function callTest(address contractAddr, uint to, uint value) public returns (bool, bytes memory, address) {
        (bool success, bytes memory data) = address(contractAddr).delegatecall(abi.encodeWithSignature("add(uint256,uint256)", to, value));

        if(!success) {
            revert();
        }

        return (success, data, contractAddr);
    }

    function tell() public view returns(uint256) {
        return (t);
    }
}