code: protected int getProxyPort(Dsn dsn) {
          return Util.parseInteger(Lookup.lookup(HTTP_PROXY_PORT_OPTION, dsn), HTTP_PROXY_PORT_DEFAULT);
      }
docs: HTTP proxy port for Sentry connections.
  
  @param dsn Sentry server DSN which may contain options.
  @return HTTP proxy port for Sentry connections.