func NewBackend(cfg *Config, logger log.Logger) Backend {
	conn, ptc, psc, err := newInstance(cfg, logger)
	if err != nil {
		logger.Fatal(err.Error())
	}

	b := &backendInstance{cfg: cfg, ptc: ptc, psc: psc,
		conn: conn, logger: logger,
	}

	go b.connectionControl()

	return b
}
func NewBackend(cfg *Config, logger log.Logger) Backend {
	conn, ptc, psc, err := newInstance(cfg, logger)
	if err != nil {
		logger.Fatal(err.Error())
	}

	b := &backendInstance{cfg: cfg, ptc: ptc, psc: psc,
		conn: conn, logger: logger,
	}

	go b.connectionControl()

	return b
}
// NewBackend returns eth back implementation.