public async Task <IActionResult> AddAddressToWhitelist( WhitelistAddressRequest request) { var result = await _addressService.AddAddressToWhitelistAsync ( address : request.Address.ToLowerInvariant(), maxGasAmount : BigInteger.Parse(request.MaxGasAmount) ); switch (result) { case AddAddressResult.SuccessResult _: return(Ok()); case AddAddressResult.HasAlreadyBeenAddedError _: return(Conflict()); default: throw new NotSupportedException( $"{nameof(_addressService.AddAddressToWhitelistAsync)} returned unsupported result."); } }