Only return POLLIN if keyboard event added a character to the buffer

src/main.rs

@@ -114,8 +114,10 @@ fn process_keyboard_data() {
             pc_keyboard::DecodedKey::RawKey(_) => (),
             pc_keyboard::DecodedKey::Unicode(ch) => KEYPRESS_BUF.lock().push_back(ch),
         }
-        for mut poll in POLLS.lock().drain(..) {
-            poll.reply(PollEvents::POLLIN);
+        if !KEYPRESS_BUF.lock().is_empty() {
+            for mut poll in POLLS.lock().drain(..) {
+                poll.reply(PollEvents::POLLIN);
+            }
         }
     }
 }