Serves as a template for new segments and forwards flows, otherwise does nothing.

Used by the pipeline package to convert segment names in configuration to actual Segment objects.

Used by Segments to register themselves in their init() functions.

Used by the tests to run single flow messages through a segment.

An extended basis for Segment implementations in the filter group.

Serves as a basis for any Segment implementations.

This interface is central to an Pipeline object, as it operates on a list of them.