void setMcastHostAddress(InetAddress addr) {
    String hostAddr = null;
    if (addr != null) {
      hostAddr = addr.getHostAddress();
    }
    mcastHostAddress = hostAddr;
  }
Sets the mcastEnabled flag for this message

@since GemFire 5.0
geode-core/src/main/java/org/apache/geode/distributed/internal/StartupMessage.java