public boolean isDurable() {
    String durableClientId = getDistributedMember().getDurableClientAttributes().getId();
    return durableClientId != null && !(durableClientId.length() == 0);
  }
Returns whether this <code>ClientProxyMembershipID</code> is durable.

@return whether this <code>ClientProxyMembershipID</code> is durable
@since GemFire 5.5
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientProxyMembershipID.java