public void setBreadcrumbsInSender() {
    if (Breadcrumbs.ENABLED) {
      String procId = "";
      long pid = getProcessorId();
      if (pid != 0) {
        procId = "processorId=" + pid;
      }

      if (recipients != null && recipients.size() <= 10) { // set a limit on recipients
        Breadcrumbs.setSendSide(procId + " recipients=" + getRecipients());
      } else {
        if (procId.length() > 0) {
          Breadcrumbs.setSendSide(procId);
        }
      }
      Object evID = getEventID();
      if (evID != null) {
        Breadcrumbs.setEventId(evID);
      }
    }
  }
sets breadcrumbs in a thread that is sending a message to another member
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionMessage.java