@Override
    public String toString() {
      return "<" + getClass().getName() + " " + getProcessorId() + " waiting for "
          + numMembers() + " replies" + (exception == null ? "" : (" exception: " + exception))
          + " from " + membersToString() + "; waiting for " + msgsBeingProcessed.get()
          + " messages in the process of being processed" + ">";
    }
Overridden to wait for messages being currently processed: This situation can come about if a
member departs while we are still processing data from that member
geode-core/src/main/java/org/apache/geode/distributed/internal/streaming/StreamingOperation.java