It shows bytes I guess

src/line_number.rs

@@ -0,0 +1,34 @@
+use ratatui::prelude::*;
+use ratatui::widgets::Widget;
+
+pub struct LineNumberWidget(pub usize, pub usize);
+
+fn usize_to_hex(mut value: usize, buffer: &mut [u8; 64]) -> &str {
+    const HEX: &[u8; 16] = b"0123456789ABCDEF";
+    let len = std::mem::size_of_val(&value);
+
+    for i in 0..len {
+        let current_byte = value & 0xff;
+
+        buffer[63 - 2 * i] = HEX[current_byte & 0x0f];
+        buffer[63 - 2 * i - 1] = HEX[current_byte >> 4];
+
+        value >>= 8;
+    }
+
+    unsafe { std::str::from_utf8_unchecked(&buffer[64 - len * 2..]) }
+}
+
+impl Widget for LineNumberWidget {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        let visible_lines = area.height as usize;
+        let mut buffer = [b'0'; 64];
+
+        let areas =
+            Layout::vertical(vec![Constraint::Length(1); visible_lines.min(self.1)]).split(area);
+
+        for (i, a) in areas.iter().enumerate() {
+            Line::from(usize_to_hex(self.0 + i * 16, &mut buffer)).render(*a, buf);
+        }
+    }
+}