The v2 logging API supports a top-level HttpRequest property that is separate from the payload:

https://cloud.google.com/logging/docs/api/reference/rest/v2/LogEntry#httprequest

Maybe this could be a special property added to the metadata argument?

Would be useful for the Winston transport PR (#1830) and the Bunyan transport lib (https://github.com/mlazarov/bunyan-stackdriver/).