...and as expected, this turns up quite some inconsistencies,
especially regarding usage of the »buffer types«.
Basically, the `PortBuilder` is responsible for the high-level functionality
and thus must ensure the nested `WiringBuilder` is addressed and parameterised
properly to connect all »slots« of the processing function.
- can use a helper function in the WiringBuilder to fill in connections
- but the actual buffer types passed over these connectinos are totally
unchecked at that level, and can not see yet how this danger can be
mitigated one level above, where the PortBuilder is used.
- it is still unclear what a »buffer type« actually means; it could
be the pointer type, but it could also imply a class or struct type
to be emplaced into the buffer, which is a special extension to the
`BufferProvider` protocol, yet seems to be used here rather to transport
specific data types required by the actual media handling library (e.g. FFmpeg)