Parent                        Child
 +----------+   +-------------------------+   +------------------------+
 |Start:    |   |Decides remote data is   |   |Detects value of 1;     |
 |$state_var|==>|needed; parent changes   |==>|Attempts to fetch the   |
 |value = 0 |   |the value from 0 to 1.   |   |data using LWP.         |
 +----------+   +-------------------------+   |                        |
    ^           +-------------------------+   |Success:  Child changes |
    |           |Detects the value of 2;  |   |the value from 1 to 2,  |
    |           |Reads the shared queue to|   |and writes the data back|
    +===========|retrieve the data, change|<==|to the shared queue.    |
    |           |the value from 2 to 0,   |   |                        |
    |           |and return to Start.     |   |Failure:  Child changes |
    |           +-------------------------+   |the value from 1 back to|
    |                                         |0 to indicate failure,  |
    +=========================================|and returns to Start.   |
                                              +------------------------+