code: func (c *Client) streamSizes() (*_SecPkgContext_StreamSizes, error) {
  	// TODO: do not retrive _SecPkgContext_StreamSizes every time (cache the data and invalidate it every time is possible can be changed: handshake, redo, ...)
  	// TODO: maybe return (header, trailer, maxmsg int, err error) instead
  	// TODO: maybe this needs to be exported
  	var ss _SecPkgContext_StreamSizes
  	ret := sspi.QueryContextAttributes(c.ctx.Handle, _SECPKG_ATTR_STREAM_SIZES, (*byte)(unsafe.Pointer(&ss)))
  	if ret != sspi.SEC_E_OK {
  		return nil, ret
  	}
  	return &ss, nil
  }
docs: // TODO: maybe move all these into a separate package or something