question: private CacheListener wrapRegionMembershipListener ( CacheListener cl ) { if ( cl instanceof RegionMembershipListener ) { return new WrappedRegionMembershipListener ( ( RegionMembershipListener ) cl ) ; } return cl ; }
target:  We wrap RegionMembershipListeners in a container when adding them at runtime, so that we can properly initialize their membership set prior to delivering events to them.