Accessing Previous Row In Asynch Script Component

I have a series of records that are timestamped and ordered by time ascending. i.e.









Time
TimeToNext


02/07/2007 11:38:22
0:00:21
<--- Need to calculate these

02/07/2007 11:38:43
0:00:22
<--- Need to calculate these

02/07/2007 11:39:06
0:00:00
<--- Need to calculate these

02/07/2007 11:39:06
0:00:36
<--- Need to calculate these

02/07/2007 11:39:42
0:00:28
<--- Need to calculate these

02/07/2007 11:40:10
0:00:26
<--- Need to calculate these

02/07/2007 11:40:36
Last Record
<--- Need to calculate these

I need to calculate the difference in time between each of these records.  The flow should go like this (psuedo):

1. Read FirstRecord

2. Read SecondRecord

3. Set FirstRecord.TimeToNext =  SecondRecord.Time - FirstRecord.Time

4. Output FirstRecord

Repeat for all rows in buffer (i.e. SecondRecord.TimeToNext = ThirdRecord.Time - SecondRecord.Time)

I am sure there is an easy way to do this with a script component, but I haven't been able to figure it out, and my head hurts from smashing it against my desk. 

Any suggestions would be greatly appreciated.