I am looking at the ERC20 implementation from openzeppelin: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/ae1bafcb48fe220257d76bfd93a237db3ebaf3df/contracts/token/ERC20/ERC20.sol
It implements the protocol so that others can just extend this contract to build their own transfer logic. But the problem I am facing is that how to transfer funds at the first time. The code:
mapping(address account => uint256) private _balances; initiate an empty map that all addresses' balance is 0. If anyone calls transfer method, it will throw ERC20InsufficientBalance error. How can I top up the balance for each accounts at the beginning?