code: func (b *basicAuth) simpleBasicAuthFunc(user, pass string, r *http.Request) bool {
  	// Equalize lengths of supplied and required credentials
  	// by hashing them
  	givenUser := sha256.Sum256([]byte(user))
  	givenPass := sha256.Sum256([]byte(pass))
  	requiredUser := sha256.Sum256([]byte(b.opts.User))
  	requiredPass := sha256.Sum256([]byte(b.opts.Password))
  
  	// Compare the supplied credentials to those set in our options
  	if subtle.ConstantTimeCompare(givenUser[:], requiredUser[:]) == 1 &&
  		subtle.ConstantTimeCompare(givenPass[:], requiredPass[:]) == 1 {
  		return true
  	}
  
  	return false
  }
docs: // simpleBasicAuthFunc authenticates the supplied username and password against
  // the User and Password set in the Options struct.