[BSP] Lots of task progress notifications with no start/end

[ckipp01]

I originally brought this up on Discord and @lolgab mentioned he was going to look into it, but I figured I'd create an issue about it just to have something in this repo that we can reference.

The issue is that if you look in the BSP logs you'll see lots of things like this:

[Trace - 02:23:53 PM] Received notification 'build/taskProgress'
Params: {
  "taskId": {
    "id": "698381564"
  },
  "eventTime": 1708089833849,
  "message": "[24/53] mill.scalalib.ZincWorkerModule.worker \u003e [3/53] mill.scalalib.ZincWorkerModule.zincLogDebug ",
  "total": 53,
  "progress": 24,
  "unit": "mill.scalalib.ZincWorkerModule.worker"
}

However, there is no build/tastStart or build/taskEnd that goes along with these. Taken from the docs

If a build/taskStart notification has been sent, the server must send build/taskFinish on completion of the same task.

The same goes for the build/taskEnd. In Discord the following was mentioned

I checked the implementation and I think it is not done at the optimal layer, since it parses the ticker logs to generate progresses. It can be done by wrapping the evaluate function so we can send the start and end of tasks and get the progress numbers directly, without parsing the logs.

I'm assuming this is referring to this code here:

mill/bsp/worker/src/mill/bsp/worker/MillBspLogger.scala

Lines 26 to 41 in 07f6f95

	override def ticker(s: String): Unit = {
	try {
	val progressString = s.split(" ")(0)
	val progress = progressString.substring(1, progressString.length - 1).split("/")
	val params = new TaskProgressParams(new TaskId(taskId.toString))
	params.setEventTime(System.currentTimeMillis())
	params.setMessage(s)
	params.setUnit(s.split(" ")(1))
	params.setProgress(progress(0).toLong)
	params.setTotal(progress(1).toLong)
	client.onBuildTaskProgress(params)
	super.ticker(s)
	} catch {
	case e: Exception => // noop
	}
	}