Add a third category of variable - Pool Transient
Currently there are two categories of variable, Pool and Transient.
Pool variables belong to the pool and are saved as data in the **Completed **and **Archived **version of the executed pool, this includes documents (which can only be defined at pool level) etc.
Transient variables belong to the step and can only be referenced in the step that they are defined in, they are destroyed at end of the step.
I would like to see a third category of variable, Pool Transient.