question: public @ NonNull ChargeRequest . Builder autoReturn ( long timeout , TimeUnit unit ) { long autoReturnMillis ; if ( timeout != RegisterApi . AUTO_RETURN_NO_TIMEOUT ) { autoReturnMillis = unit . toMillis ( timeout ) ; nonNull ( unit , "unit" ) ; if ( autoReturnMillis < RegisterApi . AUTO_RETURN_TIMEOUT_MIN_MILLIS ) { throw new IllegalArgumentException ( "timeout should be at least " + RegisterApi . AUTO_RETURN_TIMEOUT_MIN_MILLIS ) ; } if ( autoReturnMillis > RegisterApi . AUTO_RETURN_TIMEOUT_MAX_MILLIS ) { throw new IllegalArgumentException ( "timeout should be less than " + RegisterApi . AUTO_RETURN_TIMEOUT_MAX_MILLIS ) ; } } else { autoReturnMillis = RegisterApi . AUTO_RETURN_NO_TIMEOUT ; } this . autoReturnMillis = autoReturnMillis ; return this ; }
target:  <p>After a transaction completes, Square Register automatically returns to your app after the timeout you provide to this method.