tt> bytes only if the
        HTTP client fails to provide them, e.g. because the client
        crashed.)<p>
    <li>
        Next the Filter application receives the file data from the
        Web server over <tt>FCGI_DATA</tt>.  This file's last
        modification time (expressed as an integer number of seconds
        since the epoch January 1, 1970 UTC) is
        <tt>FCGI_DATA_LAST_MOD</tt>; the application may consult
        this variable and respond from a cache without reading
        the file d