code: func (o *Options) SetDefaults() {
  	// Set the socket type.
  	if o.HTTPSocketType != HTTPSocketTypeNone &&
  		o.HTTPSocketType != HTTPSocketTypeTCP &&
  		o.HTTPSocketType != HTTPSocketTypeUnix {
  		o.HTTPSocketType = HTTPSocketTypeTCP
  	}
  
  	// Set the listen address.
  	if len(o.HTTPListenAddress) == 0 {
  		o.HTTPListenAddress = ":80"
  	}
  
  	// Set the handle URL.
  	if len(o.HTTPHandleURL) == 0 {
  		o.HTTPHandleURL = "/glue/"
  	}
  
  	// Be sure that the handle URL ends with a slash.
  	if !strings.HasSuffix(o.HTTPHandleURL, "/") {
  		o.HTTPHandleURL += "/"
  	}
  
  	// Set the default check origin function if not set.
  	if o.CheckOrigin == nil {
  		o.CheckOrigin = checkSameOrigin
  	}
  }
docs: // SetDefaults sets unset option values to its default value.