pub trait Metadata:
Display
+ Send
+ Sync {
// Required methods
fn encode_to(&self, buf: &mut Vec<u8>) -> BackupResult<()>;
fn decode(buf: &[u8]) -> BackupResult<Self>
where Self: Sized;
fn hummock_version_ref(&self) -> &HummockVersion;
fn hummock_version(self) -> HummockVersion;
}