* `proxy_url`: an upstream proxy to fetch posts and/or media with, (default: `nil`)
* `send_user_agent`: should we include a user agent with HTTP requests? (default: `true`)
* `proxy_url`: an upstream proxy to fetch posts and/or media with, (default: `nil`)
* `send_user_agent`: should we include a user agent with HTTP requests? (default: `true`)