Docs: Update benchmark for x-ai/grok-4.20-beta

tests/9_stream_visualizer/outputs/x-ai_grok-4.20-beta.js

@@ -0,0 +1,30 @@
+export async function createStreamVisualizer(asyncIterable, options) {
+  const {maxPoints, alpha, width, height, yDomain} = options;
+  const d3 = await import('https://cdn.jsdelivr.net/npm/d3@7/+esm');
+  let data = [];
+  let prevEma = null;
+  for await (const v of asyncIterable) {
+    const ts = v.timestamp || Date.now();
+    const val = v.value;
+    if (prevEma === null) prevEma = val;
+    const ema = alpha * val + (1 - alpha) * prevEma;
+    prevEma = ema;
+    data.push({timestamp: ts, value: val, ema});
+    if (data.length > maxPoints) data.shift();
+  }
+  if (!data.length) return {data: [], path: ''};
+  const x = d3.scaleLinear()
+    .domain([data[0].timestamp, data[data.length - 1].timestamp])
+    .range([0, width]);
+  const y = d3.scaleLinear()
+    .domain(yDomain)
+    .range([height, 0]);
+  const line = d3.line()
+    .x(d => x(d.timestamp))
+    .y(d => y(d.ema));
+  const path = line(data);
+  return {data, path};
+}
+export default createStreamVisualizer;
+// Generation time: 1.550s
+// Result: PASS