% deno run /tmp/foo.mjs
error: Uncaught (in promise) AssertionError: Assertion failed
  console.log(querySet);
          ^
    at assert (ext:deno_console/01_console.js:199:11)
    at getKeys (ext:deno_console/01_console.js:1294:7)
    at formatRaw (ext:deno_console/01_console.js:761:14)
    at formatValue (ext:deno_console/01_console.js:545:10)
    at inspect (ext:deno_console/01_console.js:3469:10)
    at GPUQuerySet.[Deno.privateCustomInspect] (ext:deno_webgpu/01_webgpu.js:5252:12)
    at formatValue (ext:deno_console/01_console.js:487:48)
    at inspectArgs (ext:deno_console/01_console.js:3071:17)
    at console.log (ext:deno_console/01_console.js:3140:7)
    at main (file:///tmp/foo.mjs:23:11)

deno 2.0.4 (stable, release, aarch64-apple-darwin)
v8 12.9.202.13-rusty
typescript 5.6.2

async function main(navigator) {
  const adapter = await navigator.gpu?.requestAdapter();
  const canTimestamp = adapter.features.has("timestamp-query");
  const device = await adapter?.requestDevice({
    requiredFeatures: [...(canTimestamp ? ["timestamp-query"] : [])],
  });

  if (!device) {
    fail("Fatal error: Device does not support WebGPU.");
  }

  if (!canTimestamp) {
    fail(
      'Fatal error: Device does not support WebGPU timestamp query (`adapter.features.has("timestamp-query")` is false).'
    );
  }

  const querySet = device.createQuerySet({
    type: "timestamp",
    count: 2,
  });

  console.log(querySet);

  function fail(msg) {
    // eslint-disable-next-line no-alert
    alert(msg);
  }
}

await main(navigator);