Build a NodeMaven proxy string.

Targeting goes into the username. Without session_id every request gets a
new exit IP; with session_id the same exit is kept for ttl (e.g. "10m",
"1h", "24h"). country is a two-letter code; region, city and isp take the
codes from list_locations. filter is the IP quality filter, e.g. "medium".
The password is a placeholder unless the server allows revealing it.

Open one connection through the proxy and report the result.

Sends no traffic through the tunnel. Returns the gateway status, the exit IP when the gateway reports it, and how long the connection took. A 407 can mean a wrong parameter value as well as wrong credentials.

List locations available for targeting, with the codes proxy_url takes.

regions need country_code; cities and isps can be narrowed by country_code
and region_code. At most 100 rows per call: when next_offset is returned,
call again with offset=next_offset for the rest.

Remaining traffic (bytes), subscription status and whether traffic is frozen.

Traffic used over time, as parallel labels and data arrays.

Pass period, or start and end as dd-mm-yyyy (not ISO). Defaults to today.

Domains reached through the proxy, largest traffic first, with bytes and request counts.

Pass period, or start and end as dd-mm-yyyy (not ISO). Defaults to today.

Sub-users of the account with their traffic usage and limits. No passwords.

Paged from page 1. When next_page is returned, call again with it for the
rest; a page past the end comes back empty.