No, I wasn't aware of that option. In our tests we did list requests for 100 messages and then bulk requests for each messages' headers (messages.get("me", mes

No, I wasn't aware of that option. In our tests we did list requests for 100 messages and then bulk requests for each messages' headers (messages.get("me", message.getId).setFields("historyId,payload/headers")). I'll look into that option and re-run the tests.