firebase.go
func (c *Client) Init(root, auth string, api Api) {
	if api == nil {
		api = new(f)
	}

	c.api = api
	c.Url = root
	c.Auth = auth
}
func (c *Client) Init(root, auth string, api Api) {
	if api == nil {
		api = new(f)
	}

	c.api = api
	c.Url = root
	c.Auth = auth
}
// Init initializes the Firebase client with a given root url and optional auth token.
// The initialization can also pass a mock api for testing purposes.