Wrap IMAP streams into BufStream

BufWriter buffers only the writer side, but not the reader side.
With BufStream we move all the buffering to the core
and do not expect any buffering to happen inside the dependencies.

src/imap/client.rs

@@ -6,7 +6,7 @@ use std::{
 use anyhow::{Context as _, Result};
 use async_imap::Client as ImapClient;
 use async_imap::Session as ImapSession;
-use tokio::io::BufWriter;
+use tokio::io::BufStream;
 
 use super::capabilities::Capabilities;
 use super::session::Session;
@@ -96,7 +96,7 @@ impl Client {
     ) -> Result<Self> {
         let tcp_stream = connect_tcp(context, hostname, port, IMAP_TIMEOUT, strict_tls).await?;
         let tls_stream = wrap_tls(strict_tls, hostname, tcp_stream).await?;
-        let buffered_stream = BufWriter::new(tls_stream);
+        let buffered_stream = BufStream::new(tls_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let mut client = ImapClient::new(session_stream);
 
@@ -110,7 +110,7 @@ impl Client {
 
     pub async fn connect_insecure(context: &Context, hostname: &str, port: u16) -> Result<Self> {
         let tcp_stream = connect_tcp(context, hostname, port, IMAP_TIMEOUT, false).await?;
-        let buffered_stream = BufWriter::new(tcp_stream);
+        let buffered_stream = BufStream::new(tcp_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let mut client = ImapClient::new(session_stream);
         let _greeting = client
@@ -145,7 +145,7 @@ impl Client {
             .await
             .context("STARTTLS upgrade failed")?;
 
-        let buffered_stream = BufWriter::new(tls_stream);
+        let buffered_stream = BufStream::new(tls_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let client = ImapClient::new(session_stream);
 
@@ -163,7 +163,7 @@ impl Client {
             .connect(context, domain, port, IMAP_TIMEOUT, strict_tls)
             .await?;
         let tls_stream = wrap_tls(strict_tls, domain, socks5_stream).await?;
-        let buffered_stream = BufWriter::new(tls_stream);
+        let buffered_stream = BufStream::new(tls_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let mut client = ImapClient::new(session_stream);
         let _greeting = client
@@ -183,7 +183,7 @@ impl Client {
         let socks5_stream = socks5_config
             .connect(context, domain, port, IMAP_TIMEOUT, false)
             .await?;
-        let buffered_stream = BufWriter::new(socks5_stream);
+        let buffered_stream = BufStream::new(socks5_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let mut client = ImapClient::new(session_stream);
         let _greeting = client
@@ -220,7 +220,7 @@ impl Client {
         let tls_stream = wrap_tls(strict_tls, hostname, socks5_stream)
             .await
             .context("STARTTLS upgrade failed")?;
-        let buffered_stream = BufWriter::new(tls_stream);
+        let buffered_stream = BufStream::new(tls_stream);
         let session_stream: Box<dyn SessionStream> = Box::new(buffered_stream);
         let client = ImapClient::new(session_stream);
 

src/net/session.rs

@@ -2,7 +2,7 @@ use async_native_tls::TlsStream;
 use fast_socks5::client::Socks5Stream;
 use std::pin::Pin;
 use std::time::Duration;
-use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, BufStream, BufWriter};
+use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, BufStream};
 use tokio_io_timeout::TimeoutStream;
 
 pub(crate) trait SessionStream:
@@ -27,11 +27,6 @@ impl<T: SessionStream> SessionStream for BufStream<T> {
         self.get_mut().set_read_timeout(timeout);
     }
 }
-impl<T: SessionStream> SessionStream for BufWriter<T> {
-    fn set_read_timeout(&mut self, timeout: Option<Duration>) {
-        self.get_mut().set_read_timeout(timeout);
-    }
-}
 impl<T: AsyncRead + AsyncWrite + Send + Sync + std::fmt::Debug> SessionStream
     for Pin<Box<TimeoutStream<T>>>
 {