question: public void addSurpriseMemberForTesting ( DistributedMember m , long birthTime ) { if ( logger . isDebugEnabled ( ) ) { logger . debug ( "test hook is adding surprise member {} birthTime={}" , m , birthTime ) ; } latestViewWriteLock . lock ( ) ; try { surpriseMembers . put ( ( InternalDistributedMember ) m , Long . valueOf ( birthTime ) ) ; } finally { latestViewWriteLock . unlock ( ) ; } }
target:  for testing we need to be able to inject surprise members into the view to ensure that sunsetting works properly