修正外部无法构建LayerConfig的问题

src/lib.rs

@@ -108,9 +108,9 @@ pub async fn init_logging(
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct LayerConfig {
-    zinc_search_host: String,
+    pub zinc_search_host: String,
-    username: String,
+    pub username: String,
-    password: String,
+    pub password: String,
-    node_name: String,
+    pub node_name: String,
-    index_name: String,
+    pub index_name: String,
 }