Hey,
We've found that while network requests are handled by throttles, this interaction and the corresponding modifications are omitted from NetLog traces. This can leave large chunks of the request that are opaque to embedders and make it difficult to trace some classes of issues. I've started a doc on an approach we thing some potential improvements in this area would look like.
We'd love the SMEs here to take a look and provide your feedback as well as if this is something people think make sense to contribute to the Chromium project.
Document: https://docs.google.com/document/d/1NzrTyLk0vKMTsjqsuSAgAUGcKSStMGQy_77UOD9qB7s
Thank You,
Andrew Malty