Upgrade to flutter_rust_bridge V2

rust/src/api/downloader_api.rs

@@ -0,0 +1,11 @@
+use std::sync::Arc;
+use crate::downloader::{do_cancel_download, do_start_download, DownloadCallbackData};
+use crate::frb_generated::StreamSink;
+
+pub fn start_download(url: String, save_path: String, file_name: String, connection_count: u8, sink: StreamSink<DownloadCallbackData>) {
+    let _ = do_start_download(url, save_path, file_name, connection_count, Arc::new(sink));
+}
+
+pub async fn cancel_download(id: String) {
+    do_cancel_download(&id).await
+}

rust/src/api/mod.rs

@@ -0,0 +1,5 @@
+//
+// Do not put code in `mod.rs`, but put in e.g. `simple.rs`.
+//
+
+pub mod downloader_api;