Comprehensive query and read results sample

Write a sample showing
1) Use the insert+poll overload of InsertJob to start a query expecting a lot of data returned
2) use `.then` on the future returned from step 1 to invoke a callback to read the results of the finished query
3) the callback should use multiple threads to read the query results in parallel, each thread reading from its own ReadStream

首先定位 InsertJob 的 insert+poll 重载、由它返回的 future 以及 ReadStream API。围绕列出的序列构建示例，让 callback 通过彼此独立的 ReadStream 实例并行读取查询结果；完成标准是一个可正常工作的、完整的查询和读取结果示例。

由索引模型根据 Issue 内容生成。