Update one or more tasks' properties. For now, only the following properties may be updated: State (to CANCELLED)

Returns an array of updated tasks, or null if a callback is specified.

UsageReturns, action, callback)List
taskIdListID of the task or an array of multiple task IDs.
actionTaskUpdateActionsAction performed on tasks.
callbackFunction, optionalAn optional callback. If not supplied, the call is made synchronously.