sign method
Generate a signature needed for the REST authentication as defined here: https://bybit-exchange.github.io/docs/inverse/?console#t-constructingtherequest
Implementation
String sign({required String secret, required SortedMap query}) {
var queryString = '';
query.forEach((key, value) {
queryString += '$key=$value&';
});
// remove last '&' from string
queryString = queryString.substring(0, queryString.length - 1);
var msg = utf8.encode(queryString);
var key = utf8.encode(secret);
var hmac = Hmac(sha256, key);
return hmac.convert(msg).toString();
}