Input filter responsible for replaying the request body when restoring the
saved request after FORM authentication.
The original request body.
Create a new SavedRequestInputFilter.
input The saved request body to be replayed.
Set the content length on the request.
Make the filter ready to process the next request.
Return the name of the associated encoding; here, the value is null.
Set the next buffer in the filter pipeline (has no effect).
Amount of bytes still available in a buffer.
End the current request (has no effect).