优化部分语法警告

src/types.rs

@@ -1,18 +1,13 @@
 use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub enum NetMode {
     Ipv4Only,
     Ipv6Only,
+    #[default]
     DualStack,
 }
 
-impl Default for NetMode {
-    fn default() -> Self {
-        Self::DualStack
-    }
-}
-
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct TorrentInfo {
     pub info_hash: String,
@@ -85,4 +80,4 @@ impl Default for DHTOptions {
             node_queue_capacity: 100000,
         }
     }
-}
+}