StreamTransformer<S, T> class abstract interface

Transforms a Stream.

When a stream's Stream.transform method is invoked with a StreamTransformer, the stream calls the bind method on the provided transformer. The resulting stream is then returned from the Stream.transform method.

Conceptually, a transformer is simply a function from Stream to Stream that is encapsulated into a class.

It is good practice to write transformers that can be used multiple times.

All other transforming methods on Stream, such as Stream.map, Stream.where or Stream.expand can be implemented using Stream.transform. A StreamTransformer is thus very powerful but often also a bit more complicated to use.

The StreamTransformer.fromHandlers constructor allows passing separate callbacks to react to events, errors, and the end of the stream. The StreamTransformer.fromBind constructor creates a StreamTransformer whose bind method is implemented by calling the function passed to the constructor.