Passthru indication

Description
A b3270 protocol message that indicates that a registered passthru action has been invoked.

The UI must respond to this indication with a succeed or fail operation, passing back in the same p-tag value to identify this particular invocation.

If the action was invoked by the UI via the run operation (directly or indirectly) the parent-r-tag will indicate the r-tag passed to run.

Example
