Change the PassThru parameter name

[plastikfan]

... to something else. PassThru is a standard parameter name used to denote if an item should be passed through a pipeline and so it's definition here as a 'proprty bag' is not a good idea, so it should be renamed.

Or an alternative name could be Exchange (as in different entities can communicate with each other via an exchange)

[plastikfan]

New name for passThru will be tube, through which, things can be passed through.

[plastikfan]

rename _passThru first before PassThru

[plastikfan]

Something went wrong with the initial commit. not all passThru's were replaced by exchange.