[GSS](7.1.z) LogicalMessageContext.get(MessageContext.HTTP_REQUEST_HEADERS) always returns null on client-side in JBoss EAP 7

public boolean handleMessage(LogicalMessageContext context) {
  Boolean outbound = (Boolean) context.get(MessageContext.MESSAGE_OUTBOUND_PROPERTY);
  if (outbound) {
    Map<String, List<String>> headers =
        (Map<String, List<String>>) context.get(MessageContext.HTTP_REQUEST_HEADERS);
    if (headers == null) {
      headers = new HashMap<String, List<String>>();
      context.put(MessageContext.HTTP_REQUEST_HEADERS, headers);
    }
    for (Map.Entry<String, String> entry : Tracer.getEntries().entrySet()) {
      headers.put(entry.getKey(), Collections.singletonList(entry.getValue()));
    }
  }
  return true;
}