Groovy HTTPBuilder + RxJava返回一个空对象/可观察到

def login(String email, String password, String apiKey) throws HttpResponseException {

    def postBody = [
            email   : email,
            password: password
    ]

    def http = new HTTPBuilder('https://www.googleapis.com/identitytoolkit/v3/relyingparty/verifyPassword?key=' + apiKey)

    return Observable.just({ Observer observer ->

        def thread = new Thread({

            http.post(body: postBody, requestContentType: ContentType.JSON) { resp, json  ->
                println 'status code ' + resp.statusLine.statusCode
                if (resp.statusLine.statusCode == 200 || resp.statusLine.statusCode == 201) {
                    observer.onNext(json)
                } else {
                    observer.onError(new Throwable('broken'))
                }

                observer.onCompleted()

            }

            http.handler.failure = { resp ->
                observer.onError(new Throwable('failure'))
                observer.onCompleted()

            }

            http.handler.'400' = { resp ->
                observer.onError(new Throwable('bad request'))
                observer.onCompleted()

            }

        } as Runnable)

        thread.start()

        return Subscriptions.empty()
    })
}

因此，这是我在服务类中编写的用于调用Firebase auth REST API的登录名的方法。但是现在的事情是它没有返回任何数据。

我在Intellij中调试了此程序，结果发现当我执行login.subscribe时，我期望它可以将json返回给我，但是没有。

那我做错了什么？