typedef void (*SilcSFTPHandleCallback)(SilcSFTP sftp,
                                           SilcSFTPStatus status,
                                           SilcSFTPHandle handle,
                                           void *context);

    Handle callback is called when the server returns a handle to the
    client as a result of some request client has made.  The `handle'
    is the file handle and the application can use it to perform file
    operations for the handle. Each of the returned handle must be
    also closed at some point with silc_sftp_close.