logger.go
func (opt *Options) Errorf(format string, v ...interface{}) {
	if opt.Logger == nil {
		return
	}
	opt.Logger.Errorf(format, v...)
}
func (opt *Options) Errorf(format string, v ...interface{}) {
	if opt.Logger == nil {
		return
	}
	opt.Logger.Errorf(format, v...)
}
func ( opt * Options ) Errorf ( format string , v ... interface { } ) { if opt . Logger == nil { return } opt . Logger . Errorf ( format , v ... ) }
// Errorf logs an ERROR log message to the logger specified in opts or to the
// global logger if no logger is specified in opts.
Errorf logs an ERROR log message to the logger specified in opts or to the global logger if no logger is specified in opts .