The order of operations for stderr/stdout monitoring with plugins
managed to hide some important errors. For example, if something
was written to stderr *before* the port was parsed from stdout, a
very possible scenario if the plugin fails before it has even
properly sarted, then we would silently drop the stderr on the floor
leaving behind no indication of what went wrong. The new ordering
ensures that stderr is never ignored with some minor improvements
in the case that part of the port is parsed from stdout but it
ultimately ends in an error (e.g., if an EOF occurs prematurely).
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