code: func NewDefaultConfig() *Config {
  	return &Config{
  		TSIGAlgorithm:      env.GetOrDefaultString("RFC2136_TSIG_ALGORITHM", dns.HmacMD5),
  		TTL:                env.GetOrDefaultInt("RFC2136_TTL", dns01.DefaultTTL),
  		PropagationTimeout: env.GetOrDefaultSecond("RFC2136_PROPAGATION_TIMEOUT", env.GetOrDefaultSecond("RFC2136_TIMEOUT", 60*time.Second)),
  		PollingInterval:    env.GetOrDefaultSecond("RFC2136_POLLING_INTERVAL", 2*time.Second),
  		SequenceInterval:   env.GetOrDefaultSecond("RFC2136_SEQUENCE_INTERVAL", dns01.DefaultPropagationTimeout),
  		DNSTimeout:         env.GetOrDefaultSecond("RFC2136_DNS_TIMEOUT", 10*time.Second),
  	}
  }
docs: // NewDefaultConfig returns a default configuration for the DNSProvider