Import a different Serialize.

src/persister.rs

@@ -2,7 +2,7 @@ use std::convert::TryFrom;
 
 use bytes::Bytes;
 use serde::de::DeserializeOwned;
-use serde::Serialize;
+use serde::ser::Serialize;
 use serde_derive::{Deserialize, Serialize};
 
 use crate::log_array::LogArray;