@Override
  public Object getCallbackArgument() {
    Object result = getSenderCallbackArgument();
    while (result instanceof WrappedCallbackArgument) {
      WrappedCallbackArgument wca = (WrappedCallbackArgument) result;
      result = wca.getOriginalCallbackArg();
    }
    return result;
  }
Return this event's callback argument

@return this event's callback argument
geode-core/src/main/java/org/apache/geode/internal/cache/wan/GatewaySenderEventImpl.java