Add TCP idle timeout (sideshow#24)

client.go

@@ -37,6 +37,11 @@ var (
 	// TCPKeepAlive specifies the keep-alive period for an active network
 	// connection. If zero, keep-alives are not enabled.
 	TCPKeepAlive = 60 * time.Second
+	// TCPIdleTimeout specifies the maximum amount of time an idle
+	// (keep-alive) connection will remain idle before closing
+	// itself.
+	// If zero, are no limit.
+	TCPIdleTimeout = 0 * time.Second
 )
 
 // DialTLS is the default dial function for creating TLS connections for
@@ -79,10 +84,11 @@ func NewClient(certificate tls.Certificate) *Client {
 	if len(certificate.Certificate) > 0 {
 		tlsConfig.BuildNameToCertificate()
 	}
-	transport := &http2.Transport{
-		TLSClientConfig: tlsConfig,
-		DialTLS:         DialTLS,
-	}
+	transport, _ := http2.ConfigureTransport(&http.Transport{
+		IdleConnTimeout: TCPIdleTimeout,
+	})
+	transport.TLSClientConfig = tlsConfig
+	transport.DialTLS = DialTLS
 	return &Client{
 		HTTPClient: &http.Client{
 			Transport: transport,
@@ -102,9 +108,10 @@ func NewClient(certificate tls.Certificate) *Client {
 // notifications; don’t repeatedly open and close connections. APNs treats rapid
 // connection and disconnection as a denial-of-service attack.
 func NewTokenClient(token *token.Token) *Client {
-	transport := &http2.Transport{
-		DialTLS: DialTLS,
-	}
+	transport, _ := http2.ConfigureTransport(&http.Transport{
+		IdleConnTimeout: TCPIdleTimeout,
+	})
+	transport.DialTLS = DialTLS
 	return &Client{
 		Token: token,
 		HTTPClient: &http.Client{