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
static String getProcessorName(Processor processor) {
        
        if (processor instanceof ConditionalProcessor conditionalProcessor) {
            processor = conditionalProcessor.getInnerProcessor();
        }
        StringBuilder sb = new StringBuilder(5);
        sb.append(processor.getType());
        if (processor instanceof PipelineProcessor pipelineProcessor) {
            String pipelineName = pipelineProcessor.getPipelineTemplate().newInstance(Map.of()).execute();
            sb.append(":");
            sb.append(pipelineName);
        }
        String tag = processor.getTag();
        if (tag != null && tag.isEmpty() == false) {
            sb.append(":");
            sb.append(tag);
        }
        return sb.toString();
    }
    private void innerExecute(
        int slot,
        IndexRequest indexRequest,
        Pipeline pipeline,
        IntConsumer itemDroppedHandler,
        Consumer<Exception> handler
    ) {
        if (pipeline.getProcessors().isEmpty()) {
            handler.accept(null);
            return;
        }