refactor: split modules

packages/fetch/src/core.rs

@@ -0,0 +1,11 @@
+use lazy_static::lazy_static;
+
+lazy_static! {
+    static ref DEFAULT_HTTP_CLIENT_USER_AGENT: Vec<String> =
+        serde_json::from_str::<Vec<String>>(include_str!("./ua.json")).unwrap();
+}
+
+pub fn get_random_mobile_ua() -> &'static str {
+    DEFAULT_HTTP_CLIENT_USER_AGENT[fastrand::usize(0..DEFAULT_HTTP_CLIENT_USER_AGENT.len())]
+        .as_str()
+}