[Java] FlightStream: how to check whether data is available in the stream in a nonblocking way;

### Describe the usage question you have. Please include as many useful details as possible.

as the title:
How to check whether data is available in the stream in a nonblocking way;

It seems that the FlightStream API only supports fetching data by calling the `next()` method in blocking; I think a nonblocking method like `tryNext()` should also be needed.

### Component(s)

Java

從 Java FlightStream API 及其阻塞式 next() 方法開始。確定在不阻塞的情況下檢查資料可用性的預期契約，包括串流結束時的表示方式。完成的標準是，呼叫方可以透過 FlightStream API 在不阻塞的情況下檢查可用性。

由索引模型根據 Issue 內容生成。