Emails a traffic-log report for the specified campaign and date range to one or more recipients.

Submits an asynchronous Traffic Log request: Voluum generates a log of the campaign's raw traffic over the given period and emails it to the addresses in 'emails'. Sends mail to caller-supplied addresses, so confirm the recipients with the user before calling. Returns the request id immediately — the report is not ready yet; poll GET /traffic-log/{id} for its status and download link.