Adding TCP keepalives support for the broker's connection

broker.go

@@ -68,7 +68,12 @@ func (b *Broker) Open(conf *Config) error {
 	go withRecover(func() {
 		defer b.lock.Unlock()
 
-		b.conn, b.connErr = net.DialTimeout("tcp", b.addr, conf.Net.DialTimeout)
+		dialer := net.Dialer{
+			Timeout:   conf.Net.DialTimeout,
+			KeepAlive: conf.Net.KeepAlive,
+		}
+
+		b.conn, b.connErr = dialer.Dial("tcp", b.addr)
 		if b.connErr != nil {
 			b.conn = nil
 			atomic.StoreInt32(&b.opened, 0)

client_test.go

@@ -4,6 +4,7 @@ import (
 	"io"
 	"sync"
 	"testing"
+	"time"
 )
 
 func safeClose(t *testing.T, c io.Closer) {
@@ -78,6 +79,7 @@ func TestClientDoesntCachePartitionsForTopicsWithErrors(t *testing.T) {
 	seedBroker.Returns(metadataResponse)
 
 	config := NewConfig()
+	config.Net.KeepAlive = 12 * time.Millisecond
 	config.Metadata.Retry.Max = 0
 	client, err := NewClient([]string{seedBroker.Addr()}, config)
 	if err != nil {

config.go

@@ -12,6 +12,10 @@ type Config struct {
 		DialTimeout  time.Duration // How long to wait for the initial connection to succeed before timing out and returning an error (default 30s).
 		ReadTimeout  time.Duration // How long to wait for a response before timing out and returning an error (default 30s).
 		WriteTimeout time.Duration // How long to wait for a transmit to succeed before timing out and returning an error (default 30s).
+
+		// KeepAlive specifies the keep-alive period for an active network connection.
+		// If zero, keep-alives are not enabled.
+		KeepAlive time.Duration
 	}
 
 	// Metadata is the namespace for metadata management properties used by the Client, and shared by the Producer/Consumer.
@@ -126,6 +130,7 @@ func NewConfig() *Config {
 	c.Net.DialTimeout = 30 * time.Second
 	c.Net.ReadTimeout = 30 * time.Second
 	c.Net.WriteTimeout = 30 * time.Second
+	c.Net.KeepAlive = 0 * time.Second
 
 	c.Metadata.Retry.Max = 3
 	c.Metadata.Retry.Backoff = 250 * time.Millisecond