| PrefetchOperator is an operator that
| prefetches the next batch. It should
| almost always be used to read things
| from disk, so I am setting the input to
| zero blobs.
|
| For any operator that is derived from
| PrefetchOperator, it should explicitly
| call the Finalize() function in its
| destructor, so that the prefetching
| thread is properly destructed.
|
| ———–
| @note
|
| We inherit from OperatorStorage since
| we control the synchronization properties
| of this operator ourselves (we inform
| the waiting producer after we synchronize).
| This is a special-case
|
| - you should generally inherit from
| Operator directly.
|