@Override
  public void toData(DataOutput out,
      SerializationContext context) throws IOException {
    context.getSerializer().writeObject(memberID, out);
    StaticSerialization.writeString(reason, out);
  }
A LeaveRequestMessage is sent by a member of the cluster when it intends to shut down.
This informs other members of the cluster that they should not consider the shutdown to
be abnormal. No response is required.
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/messages/LeaveRequestMessage.java