Increase chunk size from 4KB to 16KB to fix performance issue. (#225)

* Increase chunk size from 4KB to 16KB to fix performance issue.

Author: HuakunShen

src/core/test.rs

@@ -183,7 +183,8 @@ pub async fn test_file_rust2rust_deprecated() -> eyre::Result<()> {
             .name("sender".to_owned())
             .spawn(async {
                 let (welcome, wormhole_future) =
-                    Wormhole::connect_without_code(transfer::APP_CONFIG.id(TEST_APPID).clone(), 2).await?;
+                    Wormhole::connect_without_code(transfer::APP_CONFIG.id(TEST_APPID).clone(), 2)
+                        .await?;
                 if let Some(welcome) = &welcome.welcome {
                     log::info!("Got welcome: {}", welcome);
                 }
@@ -258,7 +259,8 @@ pub async fn test_file_rust2rust() -> eyre::Result<()> {
             .name("sender".to_owned())
             .spawn(async {
                 let mailbox_connection =
-                    MailboxConnection::create(transfer::APP_CONFIG.id(TEST_APPID).clone(), 2).await?;
+                    MailboxConnection::create(transfer::APP_CONFIG.id(TEST_APPID).clone(), 2)
+                        .await?;
                 if let Some(welcome) = &mailbox_connection.welcome {
                     log::info!("Got welcome: {}", welcome);
                 }

src/transfer/v1.rs

@@ -581,8 +581,7 @@ pub async fn send_records<'a>(
 
     let mut hasher = Sha256::default();
 
-    // Yeah, maybe don't allocate 4kiB on the stack…
-    let mut plaintext = Box::new([0u8; 4096]);
+    let mut plaintext = vec![0u8; 16 * 1024].into_boxed_slice();
     let mut sent_size = 0;
     futures::pin_mut!(files);
     while let Some(mut file) = files.next().await.transpose()? {