@Override
  public void decSenders(boolean shared, boolean preserveOrder) {
    if (shared) {
      if (preserveOrder) {
        stats.incLong(sharedOrderedSenderConnectionsId, -1);
      } else {
        stats.incLong(sharedUnorderedSenderConnectionsId, -1);
      }
    } else {
      if (preserveOrder) {
        stats.incLong(threadOrderedSenderConnectionsId, -1);
      } else {
        stats.incLong(threadUnorderedSenderConnectionsId, -1);
      }
    }
  }
@return the timestamp that marks the start of the operation
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionStats.java