Fix IntoSink not reexported

Author: tomaka

futures/src/lib.rs

@@ -298,9 +298,10 @@ pub mod io {
 
     pub use futures_util::io::{
         AsyncReadExt, AsyncWriteExt, AsyncSeekExt, AsyncBufReadExt, AllowStdIo,
-        BufReader, BufWriter, Close, CopyInto, CopyBufInto, Flush, Lines, Read,
-        ReadExact, ReadHalf, ReadLine, ReadToEnd, ReadToString, ReadUntil,
-        ReadVectored, Seek, Window, Write, WriteAll, WriteHalf, WriteVectored,
+        BufReader, BufWriter, Close, CopyInto, CopyBufInto, Flush, IntoSink,
+        Lines, Read, ReadExact, ReadHalf, ReadLine, ReadToEnd, ReadToString,
+        ReadUntil, ReadVectored, Seek, Window, Write, WriteAll, WriteHalf,
+        WriteVectored,
     };
 }