add first benchmark

bench/src/lib.rs

@@ -0,0 +1,71 @@
+// We use empty backend for our benchmark instead of tui::backend::TestBackend to make impact of benchmark from tui-rs
+// as small as possible.
+
+use std::io;
+use tui::backend::Backend;
+use tui::buffer::Cell;
+use tui::layout::Rect;
+use tui::Terminal;
+
+pub struct DummyBackend {
+    width: u16,
+    height: u16,
+    cursor: (u16, u16),
+}
+
+impl Default for DummyBackend {
+    fn default() -> Self {
+        Self {
+            width: 80,
+            height: 24,
+            cursor: (0, 0),
+        }
+    }
+}
+
+impl Backend for DummyBackend {
+    fn draw<'a, I>(&mut self, _content: I) -> Result<(), io::Error>
+    where
+        I: Iterator<Item = (u16, u16, &'a Cell)>,
+    {
+        Ok(())
+    }
+
+    fn hide_cursor(&mut self) -> Result<(), io::Error> {
+        Ok(())
+    }
+
+    fn show_cursor(&mut self) -> Result<(), io::Error> {
+        Ok(())
+    }
+
+    fn get_cursor(&mut self) -> Result<(u16, u16), io::Error> {
+        Ok(self.cursor)
+    }
+
+    fn set_cursor(&mut self, x: u16, y: u16) -> Result<(), io::Error> {
+        self.cursor = (x, y);
+        Ok(())
+    }
+
+    fn clear(&mut self) -> Result<(), io::Error> {
+        Ok(())
+    }
+
+    fn size(&self) -> Result<Rect, io::Error> {
+        Ok(Rect {
+            x: 0,
+            y: 0,
+            width: self.width,
+            height: self.height,
+        })
+    }
+
+    fn flush(&mut self) -> Result<(), io::Error> {
+        Ok(())
+    }
+}
+
+pub fn dummy_terminal() -> Terminal<DummyBackend> {
+    Terminal::new(DummyBackend::default()).unwrap()
+}