Emulate File.stream! for a string variable

This is really odd though, running the code @vivus-ignis posted in IEx completely froze my Ubuntu 16.10 with an i7 after just a couple of lines and I had to do a hard reset.
Even more strange is the fact, that this even happens if the last line was the following:

stream |> IO.binstream(:line) |> Enum.each(fn(line) -> :noop end)

Could this be a bug in the standard library?