Base structure.
|data_out_size|. If no output data was written then all data must be read from |data_in| (user must set |data_in_read| = |data_in_size|). 3. Return RESPONSE_FILTER_DONE if all output data was written or RESPONSE_FILTER_NEED_MORE_DATA if output data is still pending.
Implement this structure to filter resource response content. The functions of this structure will be called on the browser process IO thread.