code: func transformSubProtocolHeader(header string) string {
  	tokens := strings.SplitN(header, "Bearer,", 2)
  
  	if len(tokens) < 2 {
  		return ""
  	}
  
  	return fmt.Sprintf("Bearer %v", strings.Trim(tokens[1], " "))
  }
docs: // IE and Edge do not delimit Sec-WebSocket-Protocol strings with spaces