We use `totalMetrics` with a `startTimeInNanos` and a call to `postIngest` to track the 'total time' that ingest is running for a given document. You can imagine it's a little stopwatch that we start and stop. Unfortunately, I think we're stopping the stopwatch just a little too soon, on the start side, we include the time spent transforming the document into an `IngestDocument`, but we do not include the (non-negligible) time transforming from an `IngestDocument` after the pipeline logic has run.

That is, the call to `sourceAsMap` is included:

https://github.com/elastic/elasticsearch/blob/d03664f84f15dcfcb900cf2d43121ca9d89bdda8/server/src/main/java/org/elasticsearch/ingest/IngestService.java#L905

But the call to `source` is not:

https://github.com/elastic/elasticsearch/blob/d03664f84f15dcfcb900cf2d43121ca9d89bdda8/server/src/main/java/org/elasticsearch/ingest/IngestService.java#L948

The consequence of this is that the `total` ingest stats doesn't actually reflect the true time spent in ingest code:

```
GET _nodes/stats?filter_path=nodes.*.ingest
{
  "nodes" : {
    "Aysm6ztIRne2ES5ktyuqtw" : {
      "ingest" : {
        "total" : {
          "count" : 1,
          "time_in_millis" : 110, <--- this should be a little higher than it is
```
server/src/main/java/org/elasticsearch/ingest/IngestService.java
public static final String NOOP_PIPELINE_NAME = "_none";
    public static final String INGEST_ORIGIN = "ingest";
    private static final Logger logger = LogManager.getLogger(IngestService.class);
    private final ClusterService clusterService;
    private final ScriptService scriptService;
    private final Map<String, Processor.Factory> processorFactories;
    
    
    
    
    private volatile Map<String, PipelineHolder> pipelines = Map.of();
    private final ThreadPool threadPool;
    private final IngestMetric totalMetrics = new IngestMetric();
    private final List<Consumer<ClusterState>> ingestClusterStateListeners = new CopyOnWriteArrayList<>();
    private volatile ClusterState state;
    /**