Module stage 

Core stage traits for stream processing pipelines.

Each trait represents one role in a pipeline:

• Source<T> — produces items until exhausted (None).
• Transform<In, Out> — maps an input item to zero or one output items.
• Sink<T> — consumes items (terminal).
• Fold<T, Acc> — reduces items into an accumulator (terminal).

Traits

Fold

Reduces items into an accumulator (terminal stage).

Sink

Consumes items (terminal stage).

Source

Produces items for a pipeline.

Transform

Transforms an input item into zero or one output items.