migrate to rust

src/cmd/bootstrap.rs

@@ -0,0 +1,19 @@
+use eyre::Result;
+use tokio::{fs, io, io::AsyncWriteExt};
+
+pub async fn run() -> Result<()> {
+    let mut input = io::stdin();
+    let mut out = fs::File::create("/bootstrap.tar.part").await?;
+
+    let n = io::copy(&mut input, &mut out).await?;
+
+    out.flush().await?;
+    drop(out);
+
+    eprintln!("copied {n} bytes");
+
+    fs::rename("/bootstrap.tar.part", "/bootstrap.tar").await?;
+    eprintln!("/bootstrap.tar ready to use");
+
+    Ok(())
+}