Add support for socks5 proxy

[alextokarew]

It would be nice to specify socks5 proxy settings for accessing telegram API in application itself and not to rely on external tools such as proxychains etc.

[bemyak]

You can use http proxy something like this:

use hyper::Client;
use hyper_proxy::{Intercept, Proxy, ProxyConnector};
use hyper_rustls::HttpsConnector;
use telegram_bot::HyperConnector;

...
let proxy_url = env::var("http_proxy");
let proxy = Proxy::new(Intercept::All, proxy_url.parse().unwrap());
let connector = ProxyConnector::from_proxy(HttpsConnector::new(), proxy)?;
let connector = Box::new(HyperConnector::new(
                Client::builder().build(connector),
            ))
let api = Api::with_connector(token, connector);
...

You can also configure Tor to be an HTTP proxy by adding HTTPTunnelPort 9080 in /etc/tor/torrc.

[Nanue1]

mismatched types
expected struct hyper::client::Client<_>
found struct `Client<ProxyConnector, _>

[Nanue1]

how to fix this error?