NativeDatasetFactory parameter allocator and memory pool relationship

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

@zhztheplayer
```
/**
* Constructor.
*
* @param allocator a context allocator associated with this factory. Any buffer that will be created natively will
* be then bound to this allocator.
* @param memoryPool the native memory pool associated with this factory. Any buffer created natively should request
* for memory spaces from this memory pool. This is a mapped instance of c++ arrow::MemoryPool.
* @param datasetFactoryId an ID, at the same time the native pointer of the underlying native instance of this
* factory. Make sure in c++ side the pointer is pointing to the shared pointer wrapping
* the actual instance so we could successfully decrease the reference count once
* {@link #close} is called.
* @see #close()
*/
public NativeDatasetFactory(BufferAllocator allocator, NativeMemoryPool memoryPool, long datasetFactoryId) {
this.allocator = allocator;
this.memoryPool = memoryPool;
this.datasetFactoryId = datasetFactoryId;
}
```

what's the relationship between allocator and memoryPool, does allocator allocate buffers from the memory pool or there is no such restrictions?

thanks

### Component(s)

Java

從 issue 中所示的 NativeDatasetFactory 建構函式開始，追蹤 BufferAllocator 和 NativeMemoryPool 的使用方式。在 Java API 文件中釐清它們之間的關係，包括 contributors 可以從 native 配置路徑中驗證的內容；當使用問題獲得清楚回答時，即表示完成。

由索引模型根據 Issue 內容生成。