.rust-lang.org/std/io/"><code>std::io</code></a>. Many of the submodules lack
children, like
<a href="https://doc.rust-lang.org/std/io/fs/"><code>io::fs</code></a>
and
<a href="https://doc.rust-lang.org/std/io/stdio/"><code>io::stdio</code></a>.
On the other hand,
<a href="https://doc.rust-lang.org/std/io/net/"><code>io::net</code></a>
contains submodules, so it lives in a separate directory:</p>

<span class='rusttest'>fn main() {
    io/mod.rs
   io/extensions.rs
   io/fs.rs
   io/net/mod.rs
          io/