SilcClientFileError silc_client_file_close(SilcClient client,
                                               SilcClientConnection conn,
                                               SilcUInt32 session_id);

    Closes file transmission session indicated by the `session_id'.
    If file transmission is being conducted it will be aborted
    automatically. This function is also used to close the session
    after successful file transmission. This function can be used
    also to reject incoming file transmission request.  If the
    session was already started and the monitor callback was set
    the monitor callback will be called with the monitor status
    SILC_CLIENT_FILE_MONITOR_CLOSED.