Replace unnecessary exchange util.

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/ser.rs

@@ -1,7 +1,7 @@
-use std::io::Write;
+use std::{io::Write, mem::replace};
 
 use serde::{Deserialize, Serialize, ser};
-use tuwunel_core::{Error, Result, debug::type_name, err, result::DebugInspect, utils::exchange};
+use tuwunel_core::{Error, Result, debug::type_name, err, result::DebugInspect};
 
 use crate::util::unhandled;
 
@@ -97,7 +97,7 @@ impl<W: Write> Serializer<'_, W> {
 
 	fn record_start(&mut self) -> Result {
 		debug_assert!(!self.is_finalized(), "Starting a record after serialization finalized");
-		exchange(&mut self.sep, true)
+		replace(&mut self.sep, true)
 			.then(|| self.separator())
 			.unwrap_or(Ok(()))
 	}