Update futures-util to 0.3.21

Test: cd external/rust/crates && atest --host -c
Change-Id: I0c08e14c3a0fb14c4f2e497dbe777b597ebf2ee2

1 files changed, 0 insertions, 8 deletions

diff --git a/src/io/buf_reader.rs b/src/io/buf_reader.rs
index 2d585a9..0334a9f 100644
--- a/src/io/buf_reader.rs
+++ b/src/io/buf_reader.rs
@@ -2,8 +2,6 @@ use super::DEFAULT_BUF_SIZE;
 use futures_core::future::Future;
 use futures_core::ready;
 use futures_core::task::{Context, Poll};
-#[cfg(feature = "read-initializer")]
-use futures_io::Initializer;
 use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSliceMut, SeekFrom};
 use pin_project_lite::pin_project;
 use std::io::{self, Read};
@@ -144,12 +142,6 @@ impl<R: AsyncRead> AsyncRead for BufReader<R> {
         self.consume(nread);
         Poll::Ready(Ok(nread))
     }
-
-    // we can't skip unconditionally because of the large buffer case in read.
-    #[cfg(feature = "read-initializer")]
-    unsafe fn initializer(&self) -> Initializer {
-        self.inner.initializer()
-    }
 }
 
 impl<R: AsyncRead> AsyncBufRead for BufReader<R> {