Stream.timer
You're seeing just the function
timer, go back to Stream module for more information.
Specs
timer(timer()) :: Enumerable.t()
Creates a stream that emits a single value after n milliseconds.
The value emitted is 0. This operation will block the caller by
the given time until the element is streamed.
Examples
iex> Stream.timer(10) |> Enum.to_list()
[0]