Currently, pipeline and eos does not take into account whether the streams are "valid" or not to begin with.

Consider this potentially common example:

await mkdirp(path); // async stuff
assert(req.aborted); // aborted by client
const dst = fs.createWriteStream(path);
pipeline(req, dst, common.mustCall(err => {
  assert(err != null);
}));

or less common

const dst = fs.createWriteStream(path);
await doAsyncStuff();
assert(dst.destroyed);
pipeline(req, dst, common.mustCall(err => {
  assert(err != null);
}));

This will fail... even though I believe it should error with a premature close (or something similar)?

Basically eos and pipeline makes assumptions of the arguments which are not enforced...