boolean notifyBeforeCompletion() {
    Iterator iterator = syncList.iterator();
    boolean result = true;
    while (iterator.hasNext()) {
      sync = ((Synchronization) iterator.next());
      sync.beforeCompletion();
    }
    return result;
  }
Iterate over the list of Synchronizations to complete all the methods to be performed before
completion
geode-core/src/main/java/org/apache/geode/internal/jta/TransactionImpl.java