Function accept_hdr_with_config_async 

pub async fn accept_hdr_with_config_async<S, C>(
    stream: S,
    callback: C,
    config: impl Into<Config>,
) -> Result<WebSocketStream<S>, Error>
where
    S: AsyncRead + AsyncWrite,
    C: Callback,

Available on crate feature ws only.

Similar to accept_hdr_async() but user can specify a Config.