cancel recordings in progress?

Is it possible to stop a batch recording in progress? I looked through the main.go code and it doesn't look like it's an option via the command line/undocumented API.

It would be nice to be able to issue a "cancel recording" command. Sometimes my batch recordings take a really long time and I decide to terminate the recording and start a new, modified one. Instead of just having kapacitor continue to query influx until the recording is finished -- thus wasting valuable computing resources in the meantime -- I'd like to kill the current recording in progress before I start a new, modified one.

Start with main.go and trace the existing batch recording command and any API entry points it exposes. Determine how a cancellation command should stop an in-progress recording and its ongoing InfluxDB query, then verify that a cancelled recording can be replaced by a new one without continuing to consume resources.

Written by the indexing model from the issue text.