Missing from this documentation

Here are some of the things not (yet) covered in this documentation:

Interoperating with Node streams (see example.js in @promistream/from-node-stream - this is pretty trivial and it's even entirely valid to only use Node streams in your pipeline, using this wrapper)
Concurrency (this is illustrated in the example.js for the @promistream/parallelize package)
Branching (this is illustrates in the example.js of various @promistream/fork-* packages)
Converging/merging (currently only illustrated in the example.js of the @promistream/merge-concatenate package - merge streams are still being worked on)
The exact details of what source/sink streams are responsible for (part of the unfinished spec)
How the internal peek API works (this is responsible for making concurrency work reliably)