add pathological example as a terminal perf test

build.zig

···
 
     const exe = b.addExecutable(.{
         .name = "vaxis",
-        .root_source_file = .{ .path = "examples/text_input.zig" },
+        .root_source_file = .{ .path = "examples/pathological.zig" },
         .target = target,
         .optimize = optimize,
     });

build.zig.zon

···
     .name = "vaxis",
     // This is a [Semantic Version](https://semver.org/).
     // In a future version of Zig it will be used for package deduplication.
-    .version = "0.0.0",
+    .version = "0.1.0",
 
     // This field is optional.
     // This is currently advisory only; Zig does not yet do anything

examples/pathological.zig

···
+const std = @import("std");
+const vaxis = @import("vaxis");
+const Cell = vaxis.Cell;
+
+const log = std.log.scoped(.main);
+
+const Event = union(enum) {
+    winsize: vaxis.Winsize,
+};
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const alloc = gpa.allocator();
+    var vx = try vaxis.init(Event, .{});
+    errdefer vx.deinit(alloc);
+
+    try vx.startReadThread();
+    defer vx.stopReadThread();
+    try vx.enterAltScreen();
+    try vx.queryTerminal();
+
+    outer: while (true) {
+        const event = vx.nextEvent();
+        switch (event) {
+            .winsize => |ws| {
+                try vx.resize(alloc, ws);
+                break :outer;
+            },
+        }
+    }
+
+    const timer_start = std.time.microTimestamp();
+    var iter: usize = 0;
+    while (iter < 10_000) : (iter += 1) {
+        const win = vx.window();
+        const child = win.initChild(0, 0, .{ .limit = 20 }, .{ .limit = 20 });
+        win.clear();
+        var row: usize = 0;
+        while (row < child.height) : (row += 1) {
+            var col: usize = 0;
+            while (col < child.width) : (col += 1) {
+                child.writeCell(col, row, .{
+                    .char = .{
+                        .grapheme = " ",
+                        .width = 1,
+                    },
+                    .style = .{
+                        .bg = .{ .index = @truncate(col + iter) },
+                    },
+                });
+            }
+        }
+        try vx.render();
+    }
+    const took = std.time.microTimestamp() - timer_start;
+    vx.deinit(alloc);
+    log.info("took {d}ms", .{@divTrunc(took, std.time.us_per_ms)});
+}