diff --git a/.circleci/config.yml b/.circleci/config.yml
index cbdeb1293..78ac11fb7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -4,7 +4,7 @@ version: 2.1
 executors:
   go:
     docker:
-      - image: docker.mirror.hashicorp.services/circleci/golang:1.12.8
+      - image: docker.mirror.hashicorp.services/circleci/golang:1.15
     environment:
       - TEST_RESULTS: /tmp/test-results # path to where test results are saved
 
@@ -13,20 +13,8 @@ jobs:
     executor: go
     steps:
       - checkout
-
-      # Restore go module cache if there is one
-      - restore_cache:
-          keys:
-            - memberlist-modcache-v1-{{ checksum "go.mod" }}
-
       - run: go mod download
 
-      # Save go module cache if the go.mod file has changed
-      - save_cache:
-          key: memberlist-modcache-v1-{{ checksum "go.mod" }}
-          paths:
-            - "/go/pkg/mod"
-
       # check go fmt output because it does not report non-zero when there are fmt changes
       - run:
           name: check go fmt
@@ -52,8 +40,7 @@ jobs:
 
       # run go tests with gotestsum
       - run: |
-          PACKAGE_NAMES=$(go list ./...)
-          gotestsum --format=short-verbose --junitfile $TEST_RESULTS/gotestsum-report.xml -- $PACKAGE_NAMES
+          gotestsum --format=short-verbose --junitfile $TEST_RESULTS/gotestsum-report.xml -- -race
       - store_test_results:
           path: /tmp/test-results
       - store_artifacts:
diff --git a/event_delegate.go b/event_delegate.go
index 35e2a56fd..352f98b43 100644
--- a/event_delegate.go
+++ b/event_delegate.go
@@ -49,13 +49,16 @@ type NodeEvent struct {
 }
 
 func (c *ChannelEventDelegate) NotifyJoin(n *Node) {
-	c.Ch <- NodeEvent{NodeJoin, n}
+	node := *n
+	c.Ch <- NodeEvent{NodeJoin, &node}
 }
 
 func (c *ChannelEventDelegate) NotifyLeave(n *Node) {
-	c.Ch <- NodeEvent{NodeLeave, n}
+	node := *n
+	c.Ch <- NodeEvent{NodeLeave, &node}
 }
 
 func (c *ChannelEventDelegate) NotifyUpdate(n *Node) {
-	c.Ch <- NodeEvent{NodeUpdate, n}
+	node := *n
+	c.Ch <- NodeEvent{NodeUpdate, &node}
 }
diff --git a/integ_test.go b/integ_test.go
index 849081b47..c23d04f09 100644
--- a/integ_test.go
+++ b/integ_test.go
@@ -2,6 +2,7 @@ package memberlist
 
 import (
 	"fmt"
+	"log"
 	"os"
 	"testing"
 	"time"
@@ -41,7 +42,7 @@ func TestMemberlist_Integ(t *testing.T) {
 		c.GossipInterval = 20 * time.Millisecond
 		c.PushPullInterval = 200 * time.Millisecond
 		c.SecretKey = secret
-		c.Logger = testLoggerWithName(t, c.Name)
+		c.Logger = log.New(os.Stderr, c.Name, log.LstdFlags)
 
 		if i == 0 {
 			c.Events = &ChannelEventDelegate{eventCh}
diff --git a/memberlist_test.go b/memberlist_test.go
index 38e07f77c..eac3dcae0 100644
--- a/memberlist_test.go
+++ b/memberlist_test.go
@@ -46,10 +46,8 @@ func testConfigNet(tb testing.TB, network byte) *Config {
 	config.BindAddr = getBindAddrNet(network).String()
 	config.Name = config.BindAddr
 	config.BindPort = 0 // choose free port
-	if tb != nil {
-		config.Logger = testLoggerWithName(tb, config.Name)
-	}
 	config.RequireNodeNames = true
+	config.Logger = log.New(os.Stderr, config.Name, log.LstdFlags)
 	return config
 }
 
@@ -186,7 +184,6 @@ func TestCreate_protocolVersion(t *testing.T) {
 			c := DefaultLANConfig()
 			c.BindAddr = getBindAddr().String()
 			c.ProtocolVersion = tc.version
-			c.Logger = testLogger(t)
 
 			m, err := Create(c)
 			if err == nil {
@@ -219,7 +216,6 @@ func TestCreate_secretKey(t *testing.T) {
 			c := DefaultLANConfig()
 			c.BindAddr = getBindAddr().String()
 			c.SecretKey = tc.key
-			c.Logger = testLogger(t)
 
 			m, err := Create(c)
 			if err == nil {
@@ -239,7 +235,6 @@ func TestCreate_secretKeyEmpty(t *testing.T) {
 	c := DefaultLANConfig()
 	c.BindAddr = getBindAddr().String()
 	c.SecretKey = make([]byte, 0)
-	c.Logger = testLogger(t)
 
 	m, err := Create(c)
 	require.NoError(t, err)
@@ -253,7 +248,6 @@ func TestCreate_secretKeyEmpty(t *testing.T) {
 func TestCreate_keyringOnly(t *testing.T) {
 	c := DefaultLANConfig()
 	c.BindAddr = getBindAddr().String()
-	c.Logger = testLogger(t)
 
 	keyring, err := NewKeyring(nil, make([]byte, 16))
 	require.NoError(t, err)
@@ -271,7 +265,6 @@ func TestCreate_keyringOnly(t *testing.T) {
 func TestCreate_keyringAndSecretKey(t *testing.T) {
 	c := DefaultLANConfig()
 	c.BindAddr = getBindAddr().String()
-	c.Logger = testLogger(t)
 
 	keyring, err := NewKeyring(nil, make([]byte, 16))
 	require.NoError(t, err)
@@ -1322,14 +1315,14 @@ func TestMemberlist_SendTo(t *testing.T) {
 
 	// Ensure we got the messages
 	if len(msgs1) != 1 {
-		t.Fatalf("should have 1 messages!")
+		t.Fatalf("expected 1 message, got %d", len(msgs1))
 	}
 	if !reflect.DeepEqual(msgs1[0], []byte("pong")) {
 		t.Fatalf("bad msg %v", msgs1[0])
 	}
 
 	if len(msgs2) != 1 {
-		t.Fatalf("should have 1 messages!")
+		t.Fatalf("should have 1 message, got %d", len(msgs2))
 	}
 	if !reflect.DeepEqual(msgs2[0], []byte("ping")) {
 		t.Fatalf("bad msg %v", msgs2[0])
@@ -1483,7 +1476,7 @@ func TestMemberlist_Join_IPv6(t *testing.T) {
 	c1.Name = "A"
 	c1.BindAddr = "[::1]"
 	c1.BindPort = 0 // choose free
-	c1.Logger = testLoggerWithName(t, c1.Name)
+	c1.Logger = log.New(os.Stderr, c1.Name, log.LstdFlags)
 
 	m1, err := Create(c1)
 	require.NoError(t, err)
@@ -1494,7 +1487,7 @@ func TestMemberlist_Join_IPv6(t *testing.T) {
 	c2.Name = "B"
 	c2.BindAddr = "[::1]"
 	c2.BindPort = 0 // choose free
-	c2.Logger = testLoggerWithName(t, c2.Name)
+	c2.Logger = log.New(os.Stderr, c2.Name, log.LstdFlags)
 
 	m2, err := Create(c2)
 	require.NoError(t, err)
@@ -1558,7 +1551,6 @@ func TestAdvertiseAddr(t *testing.T) {
 	c.BindAddr = bindAddr.String()
 	c.BindPort = bindPort
 	c.Name = c.BindAddr
-	c.Logger = testLoggerWithName(t, c.Name)
 
 	c.AdvertiseAddr = advertiseAddr.String()
 	c.AdvertisePort = advertisePort
@@ -1783,7 +1775,7 @@ func TestMemberlist_EncryptedGossipTransition(t *testing.T) {
 		// Set the gossip interval fast enough to get a reasonable test,
 		// but slow enough to avoid "sendto: operation not permitted"
 		conf.GossipInterval = 100 * time.Millisecond
-		conf.Logger = testLoggerWithName(t, shortName)
+		conf.Logger = log.New(os.Stderr, shortName, log.LstdFlags)
 
 		pretty[conf.Name] = shortName
 		return conf
diff --git a/net_test.go b/net_test.go
index f5326f4f6..3c15f2579 100644
--- a/net_test.go
+++ b/net_test.go
@@ -660,7 +660,6 @@ func TestEncryptDecryptState(t *testing.T) {
 		SecretKey:       []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
 		ProtocolVersion: ProtocolVersionMax,
 	}
-	config.Logger = testLogger(t)
 
 	m, err := Create(config)
 	if err != nil {
diff --git a/state.go b/state.go
index 7044f293c..5e4f7fdd7 100644
--- a/state.go
+++ b/state.go
@@ -602,13 +602,13 @@ func (m *Memberlist) gossip() {
 		addr := node.Address()
 		if len(msgs) == 1 {
 			// Send single message as is
-			if err := m.rawSendMsgPacket(node.FullAddress(), &node.Node, msgs[0]); err != nil {
+			if err := m.rawSendMsgPacket(node.FullAddress(), &node, msgs[0]); err != nil {
 				m.logger.Printf("[ERR] memberlist: Failed to send gossip to %s: %s", addr, err)
 			}
 		} else {
 			// Otherwise create and send a compound message
 			compound := makeCompoundMessage(msgs)
-			if err := m.rawSendMsgPacket(node.FullAddress(), &node.Node, compound.Bytes()); err != nil {
+			if err := m.rawSendMsgPacket(node.FullAddress(), &node, compound.Bytes()); err != nil {
 				m.logger.Printf("[ERR] memberlist: Failed to send gossip to %s: %s", addr, err)
 			}
 		}
@@ -1198,9 +1198,14 @@ func (m *Memberlist) suspectNode(s *suspect) {
 	min := suspicionTimeout(m.config.SuspicionMult, n, m.config.ProbeInterval)
 	max := time.Duration(m.config.SuspicionMaxTimeoutMult) * min
 	fn := func(numConfirmations int) {
+		var d *dead
+
 		m.nodeLock.Lock()
 		state, ok := m.nodeMap[s.Node]
 		timeout := ok && state.State == StateSuspect && state.StateChange == changeTime
+		if timeout {
+			d = &dead{Incarnation: state.Incarnation, Node: state.Name, From: m.config.Name}
+		}
 		m.nodeLock.Unlock()
 
 		if timeout {
@@ -1210,8 +1215,8 @@ func (m *Memberlist) suspectNode(s *suspect) {
 
 			m.logger.Printf("[INFO] memberlist: Marking %s as failed, suspect timeout reached (%d peer confirmations)",
 				state.Name, numConfirmations)
-			d := dead{Incarnation: state.Incarnation, Node: state.Name, From: m.config.Name}
-			m.deadNode(&d)
+
+			m.deadNode(d)
 		}
 	}
 	m.nodeTimers[s.Node] = newSuspicion(s.From, k, min, max, fn)
diff --git a/state_test.go b/state_test.go
index 9c15af848..059918af8 100644
--- a/state_test.go
+++ b/state_test.go
@@ -3,9 +3,13 @@ package memberlist
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"net"
+	"os"
+	"reflect"
 	"strconv"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -20,7 +24,7 @@ func HostMemberlist(host string, t *testing.T, f func(*Config)) *Memberlist {
 	c.Name = host
 	c.BindAddr = host
 	c.BindPort = 0 // choose a free port
-	c.Logger = testLoggerWithName(t, host)
+	c.Logger = log.New(os.Stderr, host, log.LstdFlags)
 	if f != nil {
 		f(c)
 	}
@@ -126,8 +130,8 @@ func TestMemberList_ProbeNode_Suspect(t *testing.T) {
 	time.Sleep(10 * time.Millisecond)
 
 	// One of the peers should have attempted an indirect probe.
-	if m2.sequenceNum != 1 && m3.sequenceNum != 1 {
-		t.Fatalf("bad seqnos %v, %v", m2.sequenceNum, m3.sequenceNum)
+	if s2, s3 := atomic.LoadUint32(&m2.sequenceNum), atomic.LoadUint32(&m3.sequenceNum); s2 != 1 && s3 != 1 {
+		t.Fatalf("bad seqnos, expected both to be 1: %v, %v", s2, s3)
 	}
 }
 
@@ -784,9 +788,12 @@ func TestMemberList_ProbeNode_Awareness_MissedNack(t *testing.T) {
 	probeTime := time.Now().Sub(startProbe)
 
 	// Node should be reported suspect.
+
+	m1.nodeLock.Lock()
 	if n.State != StateSuspect {
 		t.Fatalf("expect node to be suspect")
 	}
+	m1.nodeLock.Unlock()
 
 	// Make sure we timed out approximately on time.
 	if probeTime > probeTimeMax {
@@ -1420,8 +1427,8 @@ func TestMemberList_AliveNode_ChangeMeta(t *testing.T) {
 		if e.Event != NodeUpdate {
 			t.Fatalf("bad event: %v", e)
 		}
-		if e.Node != &state.Node {
-			t.Fatalf("bad event: %v", e)
+		if !reflect.DeepEqual(*e.Node, state.Node) {
+			t.Fatalf("expected %v, got %v", *e.Node, state.Node)
 		}
 		if bytes.Compare(e.Node.Meta, a.Meta) != 0 {
 			t.Fatalf("meta did not update")
diff --git a/transport_test.go b/transport_test.go
index 89176b04e..49745763f 100644
--- a/transport_test.go
+++ b/transport_test.go
@@ -19,7 +19,6 @@ func TestTransport_Join(t *testing.T) {
 	c1 := DefaultLANConfig()
 	c1.Name = "node1"
 	c1.Transport = t1
-	c1.Logger = testLogger(t)
 	m1, err := Create(c1)
 	if err != nil {
 		t.Fatalf("err: %v", err)
@@ -31,7 +30,6 @@ func TestTransport_Join(t *testing.T) {
 	c2 := DefaultLANConfig()
 	c2.Name = "node2"
 	c2.Transport = net.NewTransport("node2")
-	c2.Logger = testLogger(t)
 	m2, err := Create(c2)
 	if err != nil {
 		t.Fatalf("err: %v", err)
@@ -67,7 +65,6 @@ func TestTransport_Send(t *testing.T) {
 	c1.Name = "node1"
 	c1.Transport = t1
 	c1.Delegate = d1
-	c1.Logger = testLogger(t)
 	m1, err := Create(c1)
 	if err != nil {
 		t.Fatalf("err: %v", err)
@@ -79,7 +76,6 @@ func TestTransport_Send(t *testing.T) {
 	c2 := DefaultLANConfig()
 	c2.Name = "node2"
 	c2.Transport = net.NewTransport("node2")
-	c2.Logger = testLogger(t)
 	m2, err := Create(c2)
 	if err != nil {
 		t.Fatalf("err: %v", err)
diff --git a/util.go b/util.go
index 22bf6b440..7ca52c4cd 100644
--- a/util.go
+++ b/util.go
@@ -119,35 +119,35 @@ func moveDeadNodes(nodes []*nodeState, gossipToTheDeadTime time.Duration) int {
 	return n - numDead
 }
 
-// kRandomNodes is used to select up to k random nodes, excluding any nodes where
-// the filter function returns true. It is possible that less than k nodes are
+// kRandomNodes is used to select up to k random Nodes, excluding any nodes where
+// the exclude function returns true. It is possible that less than k nodes are
 // returned.
-func kRandomNodes(k int, nodes []*nodeState, filterFn func(*nodeState) bool) []*nodeState {
+func kRandomNodes(k int, nodes []*nodeState, exclude func(*nodeState) bool) []Node {
 	n := len(nodes)
-	kNodes := make([]*nodeState, 0, k)
+	kNodes := make([]Node, 0, k)
 OUTER:
 	// Probe up to 3*n times, with large n this is not necessary
 	// since k << n, but with small n we want search to be
 	// exhaustive
 	for i := 0; i < 3*n && len(kNodes) < k; i++ {
-		// Get random node
+		// Get random nodeState
 		idx := randomOffset(n)
-		node := nodes[idx]
+		state := nodes[idx]
 
 		// Give the filter a shot at it.
-		if filterFn != nil && filterFn(node) {
+		if exclude != nil && exclude(state) {
 			continue OUTER
 		}
 
 		// Check if we have this node already
 		for j := 0; j < len(kNodes); j++ {
-			if node == kNodes[j] {
+			if state.Node.Name == kNodes[j].Name {
 				continue OUTER
 			}
 		}
 
 		// Append the node
-		kNodes = append(kNodes, node)
+		kNodes = append(kNodes, state.Node)
 	}
 	return kNodes
 }
diff --git a/util_test.go b/util_test.go
index 44d3b86f7..516ed6ce1 100644
--- a/util_test.go
+++ b/util_test.go
@@ -257,7 +257,7 @@ func TestKRandomNodes(t *testing.T) {
 		t.Fatalf("unexpected equal")
 	}
 
-	for _, s := range [][]*nodeState{s1, s2, s3} {
+	for _, s := range [][]Node{s1, s2, s3} {
 		if len(s) != 3 {
 			t.Fatalf("bad len")
 		}
diff --git a/z_test.go b/z_test.go
deleted file mode 100644
index 400a75bfc..000000000
--- a/z_test.go
+++ /dev/null
@@ -1,25 +0,0 @@
-package memberlist
-
-import (
-	"log"
-	"strings"
-	"testing"
-)
-
-func testLogger(t testing.TB) *log.Logger {
-	return log.New(&testWriter{t}, "test: ", log.LstdFlags)
-}
-
-func testLoggerWithName(t testing.TB, name string) *log.Logger {
-	return log.New(&testWriter{t}, "test["+name+"]: ", log.LstdFlags)
-}
-
-type testWriter struct {
-	t testing.TB
-}
-
-func (tw *testWriter) Write(p []byte) (n int, err error) {
-	tw.t.Helper()
-	tw.t.Log(strings.TrimSpace(string(p)))
-	return len(p), nil
-}