Sending Ether (transfer, send, call)

transfer-vs-send-vs-call.sol

// In https://solidity-by-example.org/sending-ether/
// They say: call in combination with re-entrancy guard is the recommended method to use after December 2019.
//           (see https://consensys.github.io/smart-contract-best-practices/recommendations/#dont-use-transfer-or-send for an explanation)

// and compare the gas fees of the 3 methods:
// transfer (2300 gas, throws error)
// send (2300 gas, returns bool)
// call (forward all gas or set gas, returns bool)

// I tested all 3 methods, by sending 10 eth to a contract and then withdrawing using these functions:

// total gas used: 28098
function withdrawWithTransfer() public {
  payable(msg.sender).transfer(address(this).balance);
}

// total gas used: 28081
function withdrawWithSend() public {
  bool sent = payable(msg.sender).send(address(this).balance);
  require(sent, "Failed to send Ether");
}

// total gas used: 28171
function withdrawWithCall() public {
  (bool sent,) = payable(msg.sender).call{value: address(this).balance}("");
  require(sent, "Failed to send Ether");
}

// Conclusion
// They are all similar in gas fees. call is actually the most expensive one, but not by a lot.