diff --git a/src/io/buf_read/lines.rs b/src/io/buf_read/lines.rs
new file mode 100644
index 0000000..17ec447
--- /dev/null
+++ b/src/io/buf_read/lines.rs
@@ -0,0 +1,75 @@
+use std::mem;
+use std::pin::Pin;
+use std::str;
+
+use futures_io::AsyncBufRead;
+
+use super::read_until_internal;
+use crate::io;
+use crate::task::{Context, Poll};
+
+/// A stream of lines in a byte stream.
+///
+/// This stream is created by the [`lines`] method on types that implement [`BufRead`].
+///
+/// This type is an async version of [`std::io::Lines`].
+///
+/// [`lines`]: trait.BufRead.html#method.lines
+/// [`BufRead`]: trait.BufRead.html
+/// [`std::io::Lines`]: https://doc.rust-lang.org/nightly/std/io/struct.Lines.html
+#[derive(Debug)]
+pub struct Lines<R> {
+    pub(crate) reader: R,
+    pub(crate) buf: String,
+    pub(crate) bytes: Vec<u8>,
+    pub(crate) read: usize,
+}
+
+impl<R: AsyncBufRead> futures_core::stream::Stream for Lines<R> {
+    type Item = io::Result<String>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let Self {
+            reader,
+            buf,
+            bytes,
+            read,
+        } = unsafe { self.get_unchecked_mut() };
+        let reader = unsafe { Pin::new_unchecked(reader) };
+        let n = futures_core::ready!(read_line_internal(reader, cx, buf, bytes, read))?;
+        if n == 0 && buf.is_empty() {
+            return Poll::Ready(None);
+        }
+        if buf.ends_with('\n') {
+            buf.pop();
+            if buf.ends_with('\r') {
+                buf.pop();
+            }
+        }
+        Poll::Ready(Some(Ok(mem::replace(buf, String::new()))))
+    }
+}
+
+pub fn read_line_internal<R: AsyncBufRead + ?Sized>(
+    reader: Pin<&mut R>,
+    cx: &mut Context<'_>,
+    buf: &mut String,
+    bytes: &mut Vec<u8>,
+    read: &mut usize,
+) -> Poll<io::Result<usize>> {
+    let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
+    if str::from_utf8(&bytes).is_err() {
+        Poll::Ready(ret.and_then(|_| {
+            Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "stream did not contain valid UTF-8",
+            ))
+        }))
+    } else {
+        debug_assert!(buf.is_empty());
+        debug_assert_eq!(*read, 0);
+        // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`.
+        mem::swap(unsafe { buf.as_mut_vec() }, bytes);
+        Poll::Ready(ret)
+    }
+}
diff --git a/src/io/buf_read.rs b/src/io/buf_read/mod.rs
similarity index 63%
rename from src/io/buf_read.rs
rename to src/io/buf_read/mod.rs
index 7e6b6fb..e320375 100644
--- a/src/io/buf_read.rs
+++ b/src/io/buf_read/mod.rs
@@ -1,11 +1,17 @@
+mod lines;
+mod read_line;
+mod read_until;
+
+pub use lines::Lines;
+use read_line::ReadLineFuture;
+use read_until::ReadUntilFuture;
+
 use std::mem;
 use std::pin::Pin;
-use std::str;
 
 use cfg_if::cfg_if;
 use futures_io::AsyncBufRead;
 
-use crate::future::Future;
 use crate::io;
 use crate::task::{Context, Poll};
 
@@ -191,134 +197,6 @@ pub trait BufRead {
 
 impl<T: AsyncBufRead + Unpin + ?Sized> BufRead for T {}
 
-#[doc(hidden)]
-#[allow(missing_debug_implementations)]
-pub struct ReadUntilFuture<'a, T: Unpin + ?Sized> {
-    reader: &'a mut T,
-    byte: u8,
-    buf: &'a mut Vec<u8>,
-    read: usize,
-}
-
-impl<T: AsyncBufRead + Unpin + ?Sized> Future for ReadUntilFuture<'_, T> {
-    type Output = io::Result<usize>;
-
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let Self {
-            reader,
-            byte,
-            buf,
-            read,
-        } = &mut *self;
-        read_until_internal(Pin::new(reader), cx, *byte, buf, read)
-    }
-}
-
-#[doc(hidden)]
-#[allow(missing_debug_implementations)]
-pub struct ReadLineFuture<'a, T: Unpin + ?Sized> {
-    reader: &'a mut T,
-    buf: &'a mut String,
-    bytes: Vec<u8>,
-    read: usize,
-}
-
-impl<T: AsyncBufRead + Unpin + ?Sized> Future for ReadLineFuture<'_, T> {
-    type Output = io::Result<usize>;
-
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let Self {
-            reader,
-            buf,
-            bytes,
-            read,
-        } = &mut *self;
-        let reader = Pin::new(reader);
-
-        let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
-        if str::from_utf8(&bytes).is_err() {
-            Poll::Ready(ret.and_then(|_| {
-                Err(io::Error::new(
-                    io::ErrorKind::InvalidData,
-                    "stream did not contain valid UTF-8",
-                ))
-            }))
-        } else {
-            debug_assert!(buf.is_empty());
-            debug_assert_eq!(*read, 0);
-            // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`.
-            mem::swap(unsafe { buf.as_mut_vec() }, bytes);
-            Poll::Ready(ret)
-        }
-    }
-}
-
-/// A stream of lines in a byte stream.
-///
-/// This stream is created by the [`lines`] method on types that implement [`BufRead`].
-///
-/// This type is an async version of [`std::io::Lines`].
-///
-/// [`lines`]: trait.BufRead.html#method.lines
-/// [`BufRead`]: trait.BufRead.html
-/// [`std::io::Lines`]: https://doc.rust-lang.org/nightly/std/io/struct.Lines.html
-#[derive(Debug)]
-pub struct Lines<R> {
-    reader: R,
-    buf: String,
-    bytes: Vec<u8>,
-    read: usize,
-}
-
-impl<R: AsyncBufRead> futures_core::stream::Stream for Lines<R> {
-    type Item = io::Result<String>;
-
-    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        let Self {
-            reader,
-            buf,
-            bytes,
-            read,
-        } = unsafe { self.get_unchecked_mut() };
-        let reader = unsafe { Pin::new_unchecked(reader) };
-        let n = futures_core::ready!(read_line_internal(reader, cx, buf, bytes, read))?;
-        if n == 0 && buf.is_empty() {
-            return Poll::Ready(None);
-        }
-        if buf.ends_with('\n') {
-            buf.pop();
-            if buf.ends_with('\r') {
-                buf.pop();
-            }
-        }
-        Poll::Ready(Some(Ok(mem::replace(buf, String::new()))))
-    }
-}
-
-pub fn read_line_internal<R: AsyncBufRead + ?Sized>(
-    reader: Pin<&mut R>,
-    cx: &mut Context<'_>,
-    buf: &mut String,
-    bytes: &mut Vec<u8>,
-    read: &mut usize,
-) -> Poll<io::Result<usize>> {
-    let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
-    if str::from_utf8(&bytes).is_err() {
-        Poll::Ready(ret.and_then(|_| {
-            Err(io::Error::new(
-                io::ErrorKind::InvalidData,
-                "stream did not contain valid UTF-8",
-            ))
-        }))
-    } else {
-        debug_assert!(buf.is_empty());
-        debug_assert_eq!(*read, 0);
-        // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`.
-        mem::swap(unsafe { buf.as_mut_vec() }, bytes);
-        Poll::Ready(ret)
-    }
-}
-
 pub fn read_until_internal<R: AsyncBufRead + ?Sized>(
     mut reader: Pin<&mut R>,
     cx: &mut Context<'_>,
diff --git a/src/io/buf_read/read_line.rs b/src/io/buf_read/read_line.rs
new file mode 100644
index 0000000..7424637
--- /dev/null
+++ b/src/io/buf_read/read_line.rs
@@ -0,0 +1,49 @@
+use std::mem;
+use std::pin::Pin;
+use std::str;
+
+use futures_io::AsyncBufRead;
+
+use super::read_until_internal;
+use crate::future::Future;
+use crate::io;
+use crate::task::{Context, Poll};
+
+#[doc(hidden)]
+#[allow(missing_debug_implementations)]
+pub struct ReadLineFuture<'a, T: Unpin + ?Sized> {
+    pub(crate) reader: &'a mut T,
+    pub(crate) buf: &'a mut String,
+    pub(crate) bytes: Vec<u8>,
+    pub(crate) read: usize,
+}
+
+impl<T: AsyncBufRead + Unpin + ?Sized> Future for ReadLineFuture<'_, T> {
+    type Output = io::Result<usize>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let Self {
+            reader,
+            buf,
+            bytes,
+            read,
+        } = &mut *self;
+        let reader = Pin::new(reader);
+
+        let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
+        if str::from_utf8(&bytes).is_err() {
+            Poll::Ready(ret.and_then(|_| {
+                Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stream did not contain valid UTF-8",
+                ))
+            }))
+        } else {
+            debug_assert!(buf.is_empty());
+            debug_assert_eq!(*read, 0);
+            // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`.
+            mem::swap(unsafe { buf.as_mut_vec() }, bytes);
+            Poll::Ready(ret)
+        }
+    }
+}
diff --git a/src/io/buf_read/read_until.rs b/src/io/buf_read/read_until.rs
new file mode 100644
index 0000000..c57a820
--- /dev/null
+++ b/src/io/buf_read/read_until.rs
@@ -0,0 +1,31 @@
+use std::pin::Pin;
+
+use futures_io::AsyncBufRead;
+
+use super::read_until_internal;
+use crate::future::Future;
+use crate::io;
+use crate::task::{Context, Poll};
+
+#[doc(hidden)]
+#[allow(missing_debug_implementations)]
+pub struct ReadUntilFuture<'a, T: Unpin + ?Sized> {
+    pub(crate) reader: &'a mut T,
+    pub(crate) byte: u8,
+    pub(crate) buf: &'a mut Vec<u8>,
+    pub(crate) read: usize,
+}
+
+impl<T: AsyncBufRead + Unpin + ?Sized> Future for ReadUntilFuture<'_, T> {
+    type Output = io::Result<usize>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let Self {
+            reader,
+            byte,
+            buf,
+            read,
+        } = &mut *self;
+        read_until_internal(Pin::new(reader), cx, *byte, buf, read)
+    }
+}