Add support to peek chars via imgui rs io

src/io.rs

@@ -328,6 +328,11 @@ impl Io {
             sys::ImGuiIO_ClearInputCharacters(self.raw_mut());
         }
     }
+    /// Peek character input buffer, return a copy of entire buffer
+    pub fn peek_input_characters(&self) -> String {
+        let c16_slice = self.input_queue_characters.as_slice();
+        String::from_utf16(c16_slice).unwrap()
+    }
     pub fn update_delta_time(&mut self, delta: Duration) {
         let delta_s = delta.as_secs() as f32 + delta.subsec_nanos() as f32 / 1_000_000_000.0;
         if delta_s > 0.0 {