public void setAcked(boolean acked) {
    isAcked = acked;
  }
Make a heap copy of this off-heap event and return it. A copy only needs to be made if the
event's value is stored off-heap. If it is already on the java heap then just return "this". If
it was stored off-heap and is no longer available (because it was released) then return null.
geode-core/src/main/java/org/apache/geode/internal/cache/wan/GatewaySenderEventImpl.java