stream: abort signal in readable streams

Mostly opened for discussion about semantics.

Are these semantics correct? Do they make sense?

This is WIP: I want to test this thoroughly before considering merging + docs need to be updated.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines