def METHOD_NAME():
    vm = FakeVM()
    dispatch = FakeDispatch()
    mon = thinp.VolumeMonitor(vm, vm.log, dispatch=dispatch)
    vda = make_drive(vm.log, index=0, iface='virtio')
    vm.drives.append(vda)
    mon.on_block_threshold("vda[1]", vda.path, 512 * MiB, 10 * MiB)
    assert vda.threshold_state == BLOCK_THRESHOLD.EXCEEDED
    assert len(dispatch.calls) == 1
    part, args = dispatch.calls[0]
    assert part.func == mon._extend_drive
    assert part.args == (vda,)
    assert args == dict(timeout=EXTEND_TIMEOUT, discard=True)