- Writing frame based data.
  - All data is written from a `Data` buffer.
  - The `Data` buffer is created in `open()`.
    - The single `Data` buffer is often used to read, process and then write the data.
  - Inside `process()` the data is written to the file.
    - `outFile.write(dataBuffer, <numElements>)`
    - `<numElements>` is often the same as `numRead`
    - The `write(..)` method returns the number of elements written. However, few primitive writers check the return value when using `DataFile` since it is almost always the same as <numElements>.