[feat] provide SSE (ServerSentEvents) as alternative to websocket

[nimo23]

Describe the problem

Currently we need to use @tauriApps/plugin-websocket for unidirectional streaming (from server to client). However, there is another web standard specifically for such unidirectional streaming: Server Sent Events (SSE).

Describe the solution you'd like

Would be nice to also have @tauriApps/plugin-sse to support "server sent events".

Especially for mobile applications, SSE is a much more energy-saving alternative. Btw, in contrast to the use of the "web's native implementation", Tauri can even improve SSE communication by

• optionally bypassing a "push proxy" (https://stackoverflow.com/questions/46799463/server-sent-events-sse-connection-loss-on-mobile-phones)
• leaving SSE communication intact for the native application, use the native timer for SSE retry field (instead of the web timer)
• enabling GZIP compression of SSE message

Alternatives considered

No response

Additional context

No response

[lloydzhou]

here is stream_fetch command for tauri rust code: stream.rs

mod stream;
fn main() {
  tauri::Builder::default()
    .invoke_handler(tauri::generate_handler![stream::stream_fetch])
    .run(tauri::generate_context!())
    .expect("error while running tauri application");
}

js code: stream.ts

import { fetch as tauriStreamFetch } from "./stream"
import { fetchEventSource } from '@microsoft/fetch-event-source';

await fetchEventSource('/api/sse', {
    fetch: tauriStreamFetch,
    onmessage(ev) {
        console.log(ev.data);
    }
});