@Override
  public String toString() {
    return "InstallViewMessage(type=" + kind + "; Current ViewID=" + view.getViewId()
        + "; Previous View ID=" + previousViewId + "; " + view + "; cred="
        + (credentials == null ? "null" : "not null") + ")";
  }
A membership coordinator will send InstallViewMessages to other members when a node
in the cluster joins or leaves. There are three types of IVMs:<br>
1) PREPARE informs other member of the intent to change membership. All members of the
cluster are required to respond to this message. A non-responding member will be suspect and
may be kicke out of the cluster. A member may respond to a PREPARE message to object
due to having received a conflicting PREPARE message.<br>
2) INSTALL informs other members that all of the nodes recorded in the membership "view" have
responded to a PREPARE message and that the enclosed view defines the current cluster.<br>
3) SYNC messages are periodically broadcast to ensure that all members of the cluster
know the current cluster membership.<br>
The first two types of InstallViewMessage require a ViewAckMessage in response.
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/messages/InstallViewMessage.java