*`deploy(driver, ...)` - deploys a cluster using the specified`driver` and

other parameters specific to that driver. Returns a`cluster` instance that is

used in other methods.

* `

*`cluster->up(id)` - adds a node named`id` to the`cluster`.

*`cluster->down(id)` - removes a node named`id` from the`cluster`.

*`cluster->drop(src, dst, ratio)` - drop`ratio` packets flowing from node

`src` to node`dst`.

*`cluster->delay(src, dst, msec)` - delay packets flowing from node`src` to

node`dst` by`msec` milliseconds.

This is the troublemaker that messes with the network, nodes and time.

*`cause(cluster, trouble)` - causes the specified`trouble` in the specified

`cluster`.

*`cause(cluster, trouble, ...)` - causes the specified`trouble` in the

specified`cluster` with some trouble-specific parameters.

*`fix(cluster)` - fixes all troubles caused in the`cluster`.