implement LogTiming.Microtask, better test timings, breaking options API

tests/timing.ts

@@ -0,0 +1,25 @@
+import Logging, {
+    LoggingConfiguration,
+    LogTiming,
+} from "../mod.ts";
+
+LoggingConfiguration.logTiming = LogTiming.Microtask;
+// high-priority logs
+
+const log = new Logging("HTTP", { silent: false });
+
+Deno.serve({ port: 8080, onListen: addr => {
+    log.n(`Listen information: ${JSON.stringify(addr)}`);
+} }, async (req: Request) => {
+
+    const url = new URL(req.url);
+    if (url.pathname.includes('favicon.ico')) return new Response("Not Found", { status: 404 });
+    log.i("Received request:", url.pathname);
+
+    log.d("I/O start");
+    const res = await fetch("https://httpbin.org/delay/1");
+    log.d("I/O end");
+
+    return new Response(JSON.stringify(await res.json()), { status: 200 });
+
+});