Function atomic_write_file

pub fn atomic_write_file<F, E>(file_path: &Path, write_fn: F) -> Result<()>
where
    F: FnOnce(&mut File) -> Result<(), E>,
    E: Into<Box<dyn Error + Send + Sync>>,

Writes atomically to file.

1. Creates a temporary file with a .tmp extension in the same file directory.
2. Writes content with write_fn.
3. Fsyncs the temp file to disk.
4. Renames the temp file to the target path.
5. Fsyncs the file directory.

Atomic writes are hard:

• https://github.com/paradigmxyz/reth/issues/8622
• https://users.rust-lang.org/t/how-to-write-replace-files-atomically/42821/13