*: add support for socket options

Signed-off-by: Sam Batschelet <sbatsche@redhat.com>

server/embed/config.go

@@ -232,6 +232,9 @@ type Config struct {
 	// before closing a non-responsive connection. 0 to disable.
 	GRPCKeepAliveTimeout time.Duration `json:"grpc-keepalive-timeout"`
 
+	// SocketOpts are socket options passed to listener config.
+	SocketOpts transport.SocketOpts
+
 	// PreVote is true to enable Raft Pre-Vote.
 	// If enabled, Raft runs an additional election phase
 	// to check whether it would get enough votes to win
@@ -398,6 +401,8 @@ func NewConfig() *Config {
 		GRPCKeepAliveInterval: DefaultGRPCKeepAliveInterval,
 		GRPCKeepAliveTimeout:  DefaultGRPCKeepAliveTimeout,
 
+		SocketOpts: transport.SocketOpts{},
+
 		TickMs:                     100,
 		ElectionMs:                 1000,
 		InitialElectionTickAdvance: true,