final gsnTx = GsnTransactionDetails(
from: accountAddress,
data: tx.data,
value: "0",
to: contractAddress,
gas: gas.toString(),
maxFeePerGas: maxFeePerGas.toString(),
maxPriorityFeePerGas: maxPriorityFeePerGas.toString(),
);
await amoy.relay(gsnTx)
// relay arbitrary tx through our gasless relayer. see complete Flutter example at
// https://github.com/rally-dfs/flutter-example-app/tree/main/app/lib/services/nft.dart