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
}
    /**
     * Recursive method to obtain all of the non-failure processors for given compoundProcessor. Since conditionals are implemented as
     * wrappers to the actual processor, always prefer the actual processor's metric over the conditional processor's metric.
     * @param compoundProcessor The compound processor to start walking the non-failure processors
     * @param processorMetrics The list of {@link Processor} {@link IngestMetric} tuples.
     * @return the processorMetrics for all non-failure processor that belong to the original compoundProcessor
     */
    private static List<Tuple<Processor, IngestMetric>> getProcessorMetrics(
        CompoundProcessor compoundProcessor,
        List<Tuple<Processor, IngestMetric>> processorMetrics
    ) {
        
        for (Tuple<Processor, IngestMetric> processorWithMetric : compoundProcessor.getProcessorsWithMetrics()) {
            Processor processor = processorWithMetric.v1();
            IngestMetric metric = processorWithMetric.v2();
            if (processor instanceof CompoundProcessor cp) {
                getProcessorMetrics(cp, processorMetrics);
            } else {
                
                if (processor instanceof ConditionalProcessor cp) {
                    metric = (cp.getMetric());
                }
                processorMetrics.add(new Tuple<>(processor, metric));
            }
        }
        return processorMetrics;
    }
    /**
     * Used in this class and externally by the {@link org.elasticsearch.action.ingest.ReservedPipelineAction}