ci: test with the race detector (#277)

.circleci/config.yml

@@ -9,6 +9,9 @@ workflows:
       - ci-go/build
       - ci-go/lint
       - ci-go/test
+      - ci-go/test:
+          race: true
+          name: "ci-go/test/race"
       - ci-go/benchmark:
           tolerance: 50
           requires:

bitswap_test.go

@@ -245,7 +245,7 @@ func TestLargeSwarm(t *testing.T) {
 	if detectrace.WithRace() {
 		// when running with the race detector, 500 instances launches
 		// well over 8k goroutines. This hits a race detector limit.
-		numInstances = 50
+		numInstances = 20
 	} else if travis.IsRunning() {
 		numInstances = 200
 	} else {