Libei support - input emulation (#33)

Add support for input emulation through libei!

src/backend/producer/x11.rs

@@ -1,42 +1,32 @@
-use std::io::Result;
-use std::os::fd::{AsRawFd, self};
-use std::vec::Drain;
+use std::io;
+use std::task::Poll;
 
-use tokio::io::unix::AsyncFd;
+
+use futures_core::Stream;
 
 use crate::event::Event;
 use crate::producer::EventProducer;
 
 use crate::client::{ClientEvent, ClientHandle};
 
-pub struct X11Producer {
-    pending_events: Vec<(ClientHandle, Event)>,
-}
+pub struct X11Producer { }
 
 impl X11Producer {
     pub fn new() -> Self {
-        Self {
-            pending_events: vec![],
-        }
-    }
-}
-
-impl AsRawFd for X11Producer {
-    fn as_raw_fd(&self) -> fd::RawFd {
-        todo!()
+        Self { }
     }
 }
 
 impl EventProducer for X11Producer {
     fn notify(&mut self, _: ClientEvent) { }
 
-    fn read_events(&mut self) -> Drain<(ClientHandle, Event)> {
-        self.pending_events.drain(..)
-    }
-
     fn release(&mut self) {}
+}
 
-    fn get_async_fd(&self) -> Result<AsyncFd<fd::RawFd>> {
-        todo!()
+impl Stream for X11Producer {
+    type Item = io::Result<(ClientHandle, Event)>;
+
+    fn poll_next(self: std::pin::Pin<&mut Self>, _cx: &mut std::task::Context<'_>) -> std::task::Poll<Option<Self::Item>> {
+        Poll::Pending
     }
 }