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
Write a sample showing
.thenon the future returned from step 1 to invoke a callback to read the results of the finished query