getTxParams method
Implementation
Future<Map> getTxParams(String from, String to, String token, String address,
String amount, int decimals, String signer) async {
assert(_runner != null, 'bridge not init');
final Map res = await _runner?.evalJavascript(
'bridge.getTxParams("$from", "$to", "$token", "$address", "$amount", $decimals, "$signer")');
return res;
}