Function ws_tool::protocol::async_req_handshake

pub async fn async_req_handshake(
    stream: &mut WsAsyncStream, 
    mode: &Mode, 
    uri: &Uri, 
    protocols: String, 
    extensions: String, 
    version: u8, 
    extra_headers: HashMap<String, String>
) -> Result<(String, Response<()>), WsError>

perform http upgrade

NOTE: low level api