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
if (type.equals(oldType)) {
                                metric.add(oldMetric);
                            }
                        }
                    }
                }
            } catch (ElasticsearchParseException e) {
                Pipeline pipeline = substitutePipeline(newConfiguration.getId(), e);
                newPipelines.put(newConfiguration.getId(), new PipelineHolder(newConfiguration, pipeline));
                if (exceptions == null) {
                    exceptions = new ArrayList<>();
                }
                exceptions.add(e);
            } catch (Exception e) {
                ElasticsearchParseException parseException = new ElasticsearchParseException(
                    "Error updating pipeline with id [" + newConfiguration.getId() + "]",
                    e
                );
                Pipeline pipeline = substitutePipeline(newConfiguration.getId(), parseException);
                newPipelines.put(newConfiguration.getId(), new PipelineHolder(newConfiguration, pipeline));
                if (exceptions == null) {
                    exceptions = new ArrayList<>();
                }
                exceptions.add(parseException);
            }
        }
        
        
        for (Map.Entry<String, PipelineHolder> entry : existingPipelines.entrySet()) {
            if (newIngestMetadata.getPipelines().get(entry.getKey()) == null) {