(self)
Initiate cancellation.

    Advises the RPC system that the caller desires that the RPC call be
    canceled.  The RPC system may cancel it immediately, may wait awhile and
    then cancel it, or may not even cancel the call at all.  If the call is
    canceled, the "done" callback will still be called and the RpcController
    will indicate that the call failed at that time.
Initiate cancellation.
Initiate cancellation .
def StartCancel(self):
    """Initiate cancellation.

    Advises the RPC system that the caller desires that the RPC call be
    canceled.  The RPC system may cancel it immediately, may wait awhile and
    then cancel it, or may not even cancel the call at all.  If the call is
    canceled, the "done" callback will still be called and the RpcController
    will indicate that the call failed at that time.
    """
    raise NotImplementedError
def StartCancel ( self ) : raise NotImplementedError