public IClient CreateNewClient(string phone, string name)
        {
            var client = new ClientStub(_rng.Next(), name, phone);

            _clientsByPhone.Add(phone, client);
            _clientsById.Add(client.ID, client);
            return(client);
        }
        public DataProviderStub()
        {
            const string phone         = "123456789";
            IClient      defaultClient = new ClientStub(_rng.Next(), "Алексей Авершин", phone);

            _clientsByPhone.Add(phone, defaultClient);
            _clientsById.Add(defaultClient.ID, defaultClient);
        }