class connect :?proxy:#Uq_engines.client_endpoint_connector -> Uq_engines.connect_address -> float ->client
connect addr timeout: Connects with the server at addr, and
      configure that I/O operations time out after timeout seconds of
      waiting.
Example:
  let addr =
    `Socket(`Sock_inet_byname(Unix.SOCK_STREAM, "www.domain.com", 25),
            Uq_client.default_connect_options) in
  let client =
    new Netsmtp.connect addr 60.0