code: func (c *Cors) isMethodAllowed(method string) bool {
  	if len(c.allowedMethods) == 0 {
  		// If no method allowed, always return false, even for preflight request
  		return false
  	}
  	method = strings.ToUpper(method)
  	if method == "OPTIONS" {
  		// Always allow preflight requests
  		return true
  	}
  	for _, m := range c.allowedMethods {
  		if m == method {
  			return true
  		}
  	}
  	return false
  }
docs: // isMethodAllowed checks if a given method can be used as part of a cross-domain request
  // on the endpoing