In the life cycle of an instance of this class, the answer is yes. You know, the `split(index)` here indicates a single file. Because I set `isSplitable()` in `BatchFileInputFormat` to false.

The `nextKeyValue()` could be called several times, until not more bytes left in the `split(index)`, by `nextKeyValue()` function in `CombineFileInputFormat`, and eventually the `compute()` in `HadoopRDD`. It will read an entire file in bytes, and I encapsulate these bytes into `Text`.