protected static void send(Set others, DistributionManager dm, ReplyProcessor21 proc) {
      ElderInitMessage msg = new ElderInitMessage();
      msg.processorId = proc.getProcessorId();
      msg.setRecipients(others);
      if (logger.isTraceEnabled(LogMarker.DLS_VERBOSE)) {
        logger.trace(LogMarker.DLS_VERBOSE, "ElderInitMessage sending {} to {}", msg, others);
      }
      dm.putOutgoing(msg);
    }
Note the synchronization; we can only process one response at a time.
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/ElderInitProcessor.java