open(Host, Port) -> open(Host, Port, #{}) open(Host, Port, Opts) -> {ok, pid()} | {error, Reason} Host :: inet:hostname() | inet:ip_address() Port :: inet:port_number() Opts :: gun:opts() Reason :: {options, OptName} | {options, {http | http2 | socks | ws, OptName}} | any() OptName :: atom()