use BufWriter

src/main.rs

@@ -10,7 +10,7 @@ use encoding::label::encoding_from_whatwg_label;
 use encoding::EncodingRef;
 use encoding::{DecoderTrap, EncoderTrap};
 use regex::Regex;
-use tokio::io::AsyncReadExt;
+use tokio::io::{AsyncReadExt, BufWriter, AsyncWriteExt};
 use tokio::sync::mpsc::{self, UnboundedReceiver, UnboundedSender};
 use tokio::{fs, task};
 
@@ -143,16 +143,18 @@ async fn writer_task(
     output_filename: String,
     compression: Compression,
 ) {
-    let mut outfile = fs::File::create(output_filename)
+    let outfile = fs::File::create(output_filename)
         .await
         .expect("output file");
-    let mut writer = ZipFileWriter::new(&mut outfile);
+    let mut buf = BufWriter::with_capacity(100 * 1024 * 1024, outfile);
+    let mut writer = ZipFileWriter::new(&mut buf);
 
     while let Some(FileData { name, data }) = rx.recv().await {
         let opts = EntryOptions::new(name, compression);
         writer.write_entry_whole(opts, &data).await.unwrap();
     }
     writer.close().await.unwrap();
+    buf.flush().await.unwrap();
     println!("write done ✅");
 }