question: public long backoff ( int attempt ) { long duration = base * ( long ) Math . pow ( factor , attempt ) ; if ( jitter != 0 ) { double random = Math . random ( ) ; int deviation = ( int ) Math . floor ( random * jitter * duration ) ; if ( ( ( ( int ) Math . floor ( random * 10 ) ) & 1 ) == 0 ) { duration = duration - deviation ; } else { duration = duration + deviation ; } } if ( duration < 0 ) { duration = Long . MAX_VALUE ; } return Math . min ( Math . max ( duration , base ) , cap ) ; }
target:  Return the duration (in milliseconds) for which you should backoff. 