public async Task <(JsonRpc response, string error)> PostAsync(JsonRpc request, CancellationToken cancellation) { try { if (JsonRpc.TryParse(await provider.PostAsync(request, cancellation), out JsonRpc response)) { if (response.HasError) { return(null, response.ErrorMessage); } return(response, null); } return(null, "response not parsable"); } catch (Exception ex) { return(null, ex.Message); } }