Add benchmark README and latest numbers

benchmark/README.md

@@ -0,0 +1,51 @@
+# Benchmarks
+
+## How to run
+
+To run your benchmark, just:
+```
+$ npm run bench
+```
+
+If you're interested in writing benchmarking for other APIs, please write a benchmark in the `benchmark/index.js` module. Please refer to the `benchmark/tracer.js` or `benchmark/propagator.js` for more comprehensive examples.
+
+## Results
+
+# `0.3.3` release
+
+```
+Beginning BasicTracerRegistry Benchmark...
+  7 tests completed.
+
+  #startSpan                          x 79,704 ops/sec ±4.46% (10 runs sampled)
+  #startSpan:parent                   x 55,975 ops/sec ±1.90% (10 runs sampled)
+  #startSpan with attribute           x 84,479 ops/sec ±2.82% (10 runs sampled)
+  #startSpan with 30 attributes       x 36,239 ops/sec ±2.67% (10 runs sampled)
+  #startSpan with 100 attributes      x  3,716 ops/sec ±1.92% (10 runs sampled)
+  #startSpan with SimpleSpanProcessor x  5,440 ops/sec ±39.90% (10 runs sampled)
+  #startSpan with BatchSpanProcessor  x  2,284 ops/sec ±6.51% (10 runs sampled)
+
+Beginning NodeTracerRegistry Benchmark...
+  7 tests completed.
+
+  #startSpan                          x 81,777 ops/sec ±4.32% (10 runs sampled)
+  #startSpan:parent                   x 57,455 ops/sec ±3.87% (10 runs sampled)
+  #startSpan with attribute           x 85,139 ops/sec ±4.09% (10 runs sampled)
+  #startSpan with 30 attributes       x 38,240 ops/sec ±1.95% (10 runs sampled)
+  #startSpan with 100 attributes      x  3,670 ops/sec ±6.85% (10 runs sampled)
+  #startSpan with SimpleSpanProcessor x  4,504 ops/sec ±37.04% (10 runs sampled)
+  #startSpan with BatchSpanProcessor  x  1,847 ops/sec ±5.26% (10 runs sampled)
+
+
+Beginning B3Format Benchmark...
+  2 tests completed.
+
+  #Inject  x 5,569,330 ops/sec ±1.44% (10 runs sampled)
+  #Extract x 4,882,488 ops/sec ±3.72% (10 runs sampled)
+
+Beginning HttpTraceContext Benchmark...
+  2 tests completed.
+
+  #Inject  x 13,423,892 ops/sec ±4.62% (10 runs sampled)
+  #Extract x  1,673,804 ops/sec ±2.29% (10 runs sampled)
+```

benchmark/tracer.js

@@ -21,7 +21,8 @@ const setups = [
 
 for (const setup of setups) {
   console.log(`Beginning ${setup.name} Benchmark...`);
-  const tracer = setup.registry.getTracer("benchmark");
+  const registry = setup.registry;
+  const tracer = registry.getTracer("benchmark");
   const suite = benchmark()
     .add('#startSpan', function () {
       const span = tracer.startSpan('op');